US2819540A - Control system for clothes dryers and combination washer-dryers - Google Patents

Description

Jan. 14, 1958 J. w. TOMA ETAL 2,819,540

- CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS Filed May 14, 1956 4 Sheets-Sheet 1 FIG.'

INVENTORS.

8| \JOHN w.-TOMA JOHN E. RYAN- THEIR ATT RNEY Jan. 14, 1958 r w. To ErAL 2,819,540

CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS Filed May 14, 1956 4 Sheets-Sheet 2 F'IG.3

a o cm JNVENTORS & JOHN w. TOMA JOHN 5. RYAN' THEIR ATTORNEY Jan. 14, 1958 J. w. TOMA'ETAL CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS 4 Sheet s-Sheet s Filed May 14, 195,6v

FIG.4

INVENTORS. & JOHN W. TOMA 4 JOHN E. RVAN' THEIR ATTORNEY J. W. TOMA El AL SYS Jan. 14, 1958 2,819,540 CONTROL TEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS Filed May 14. 1956 4 Sheets-Sheet 4 MW MW b0 00 F mh H .Y .HP v, TI..|I.IIIIWM.T.

pm w h 30%:gr www "H EJR ATTORNEY United States Patent CON TROL. SYSTEM FOR" CLOTHES DRYERS AND New York Application May-14, 1956, Serial No. secess- 9 claimst urea-45y Our-invention relates: to clothes dryers and more partie ularly itrrelates to control systems fort-automatically: COI1itrolling. such. machines:- during: the. drying; operation; While thisinvention has general applicationto clothes dryers; it is particularlyuseful imeornb-inati'on. clothes washing and drying machines.

Inwthes copending'aapplication of Walter E; Gray,.lr.,. S. N. 512,612,. filedlune 2,2 1955,:and'1 assigned. to the same :a'ssignee as: the present invention, there is. describedand claimed. an .:improv'ed l.control system for: combination washer-dryers. Thepwasher-di'yer of the Gray application: is provided With' tWOH separate. heating elements; for use duringithedryingtoperation and-thercontrol systernds so; arranged that both. elements are energized: at beginning. of: the operation; However; toward theend ofi theaoperation one of the elements is .de.energ-ized"-and the operation-1 is: completed on the reduced? power available, from the other. element alone. The reason for thiSsCOIIiIOhSBqUWlCG is that the predetermined maximumwattage available from the twoheaters may. be advantageously used: for. moisa tureextraction so lOHg'u-QS there. is surface moisture remaining on the clothes; But afte-r-thesurtacemoisture is removed, the maximum; Wattage supplies moreheat. to. the machine than can. be usedi for the evaporation of the internal moisture .within the fabrics being dtied whereby if it were continued a rapid rise-in the-temperature within the machine would result... Themaximum -rate ot dryin-g of the internal moisture within the fabrics .is not a direct.

function of the heatiappliedpbut rather. after acertain point in heatapplicati-on no. matterrhow much more-power. is applied withinereasonable 1imits,.the rate. of. evaporation will not increase... beyond that used formoisture extraction would oftcourse,

cause arise: in the temperature within the: machine. Thus inthe Gray control system l the power isreducedtoward the end of the dryingoperation,, .by the .de-energization.

of the: one heater, to. ava-Iue which etficiently removes. the moisture remaining... in the fabrics, without. causing, any overheating of. the machine- In other words byreducing the. power. only. enough heat. is. supplied to. evaporate efliciently. themoisture from, the!- fabrics. without any. ap-.-

trip. point the circuit. to the one heating element is opened so as to. de-energiize itfandlreduce the "heat applied to the clothes. Atthe. second trip point the second heating element is de-energized and'the'operation of'themachine terminated. The secondjtrip pointis, of'course, selected attlie' temperature which" indicates the clotheshave dried;

The remaining-- increment of power:

'ice

i. e. which indicates that both the surface and the internal-moisture: have: been removed from the clothes. The first trip point is selectedra-ta temperature sufficiently below the secondxtrip pointsto insure; that the power input is' reduced'1early-enoughio prevent temperature overshoot or heating of the machine beyond the second trip. point.

Our invention-hastfoirits primaryobject the provision of a newandimprovedfcontrol'. for the dryingtopertrtion. of a laundrywmachine whieh control uses. a thermostathaving but a single trip point in order first toreduce the power toward theend: ofwt-hew: drying operation; and then to terminate the operation completely when the clothes: have finishedadrying:atthe reducedpower: This control with the singleleveldhermostaflnot only results in. a'shorter drying operation but. also is less expensive due to a decreased LCOStEfOI" the thermostat.

Another objeetof-ourvinvention. is to provide" an improved control-system1 particularly adapted for use. in combination washer-dryersp which; utilizes a single level thermostat andtatimers. operated sequencecontrol mechanism first to apply full heat during the drying operation, then toreduce theheat and. finally terminatethe operationof the washer-dryer-after' a cool down period. The sequence control mechanism. utilized. with the single level thermostatfor so controlling. the drying operation may advantageously bettheosame mechanismasis used to control thewashing operation-of the washer-dryer.

In carryingout our invention in oneform thereof, we provide a. clothesdryert having clothestumbling means and a pair ofielectrioal. heating elements for supplying heat to the..clothes.,duringthe drying operation. lnthe washer-dryer we-incorporate anew. and improved control system embodying our invention. This control system utilizes a single-levelflthermostat and a timer operated sequence controlfmechanismior controlling the heating elements during thecdryingw operation. The thermostat trips atapIedeteIminedhi-gh temperature and resets at a predetermined lower temperature, and. the thermostat and the sequence controlmechanism are so arranged in the system that thesystem energizes-both the heating elements simultaneously at the. beginning. of the drying operation. until the thermostat trips for the first time- Thereby maximum power'is supplied tothe clothes during the first partoiftheoperation. After thethermostat resets after tripping the first time, .the system thenenergizes only one of the elmentsfor applying reduced heat to the clothes. This reduced'heat application continues until the thermostat. trips a second time in response to the reduced heat, and .atfthat pointthe system de-energizesthe second heater also and terminates thedrying operation. By this combineduseoffthe single. level thermostat and the sequence control mechanism whereby the thermostat trips twice at the same temperature for controlling the heaters, once to reduce the powenand the second time to terminate theoperation otfthemachine, the system so energizes the heating elements that. a. relatively short drying time is produced. The short drying time is,.ot' course, an ad vantageousfeature foricombination washer-dryers as well as forclothes dryers. Also, the system is particularly aclvantageouscost wiseiu' washer-dryers since it requires.

only the addition of an inexpensive single level thermostat to the sequencecontrol mechanism which must be provided anyway for the washing. operation.

The: subject matter Which.we regard as our invention. is. particularlypointed out. and distinctly claimedinthe" concluding portion of this specification.

Fig. l is a front elevational view of a combination washer-dryer, with a portion thereof being broken away to illustrate interior details;

Fig. 2 is a fragmentary cross sectional view taken on line 22 of Fig. 1;

Fig. 3 is a rear View of the machine with the rear panel removed to illustrate details;

Fig. 4 is a side elevational view of the machine, partially in section and with certain surfaces broken away to show details; and

Fig. 5 is a schematic electrical wiring diagram and sequence control cam chart illustrating a control system for the machine, which system embodies our invention in one form thereof.

eferring now to Fig. 1, I have shown therein a domestic laundry machine comprising a combination washer and dryer. The operating elements of the machine are included within an outer cabinet structure including a wrap-around central section 1. The central section 1 is supported on a base and toeboard assembly 2 and carries a separate top 3 provided with an integral backsplash panel 4. Access to the interior of the machine is provided by a door 5 mounted on concealed hinges and opened by means of a knee-operated latch control number 6.

The machine is so constructed that when a load of soiled clothes is placed therein, it proceeds through a sequence of operations, first washing the clothes and then drying them. In order to provide complete flexibility of operation of the machine a number of operator controls are included therein, these controls being mounted on the backsplash panel 4. The controls include, for example, a plurality of push buttons consisting of an ofi button 7, hot and warm water buttons 8 and 9, a dryer control or omit dry button 10, and a water heater button 11. A rotatable control knob 12 is provided for convenient operator selection of any separate sequence of operation, and a second control knob 13 is included for operator selection of operating temperatures for the drying portion of the cycle of operation. As will be seen hereinafter these controls provide for complete flexibility of operation of the machine.

As shown in Fig. 4, the machine is of the horizontal axis type. That is, it has a clothes basket or drum 14 mounted for rotation on a generally horizontal axis within an outer enclosing tub structure 15. The basket 14 comprises a cylindrical shell 16 which is closed at its rear end by means of a suitable wall or plate 17. The basket also includes a front wall 18 which is formed so as to define an access or loading opening to the basket. The basket is rotatably supported by a shaft 19 which is mounted in an elongated bearing 20 supported from the rear wall 21 of the tub. The tub is provided with an opening 22 in the front wall thereof, which is aligned with the access opening to the basket so that clothes may be placed into or removed from the basket. The door 5 (see Fig. l) seals against a suitable gasket 22a to close this opening during operation of the machine.

During the operation of the machine the basket 14 is driven from an electric motor 23 through a drive including a pair of flexible belts 24 and 25 (see Figs. 2 and 3). The belt 24 connects the output pulley 26 of the motor 23 to the input pulley 27 of a transmission assembly 28. The belt 25 connects the output pulley 29 of the transmission assembly 28 to a basket drive pulley 30 mounted on the shaft 19 of the clothes-tumbling basket 14. The transmission assembly 28 is of the multiple speed type, that is, the ratio thereof can be changed so that the basket is driven at two different speeds. The transmission assembly thus provides one basket speed for clothes tumbling and another basket speed for centrifugal extraction. The ratio of the transmission assembly is changed by means of a suitable spring biased, solenoid actuated plunger 31. When the solenoid 32 controlling the plunger 31 is deenergized, the transmission ratio is such that the basket is driven at a suitable speed for washing and tumbling clothes, for example, 44 revolutions per minute. However, when the solenoid 32 is energized, the plunger 31 changes the ratio of the transmission so that the basket is driven at a suitable speed for centrifugal extraction, for example, 200 revolutions per minute.

During the operation of the machine the basket 14 is continuously rotated by means of this drive. The preferred sequence of operations through which the machine proceeds to Wash and dry the clothes contained therein is described hereinafter.

To heat the clothes during the drying portion of the cycle and also to warm the wash water during the washing portion of the cycle when desired, there is provided in the machine a heater assembly including two heaters 35 and 36. These heaters are mounted Within the upper portion of the tub 15 so that when energized, they heat the basket 14. The heating elements are preferably of the sheathed type in which a resistance wire is maintained in spaced relation with an outer sheath by a highly compressed, granulated, heat conducting, electrically insulating compound such as magnesium oxide. Such heating elements are sold under the trademark of Calrod and are available commercially. When the heaters are energized during the washing cycle, they heat the water by first heating the basket. Then as the basket dips into the wash water at the bottom of the tub, it in turn heats the water. In other words, the rotating basket serves as an effective heat transfer means between the heating elements and the water or other Washing liquid. When the heaters are energized during the drying cycle, the heat transferred to the basket is then passed on to the clothes to cause vapor migration out of the clothes. Since the outer cylindrical shell of the basket is perforated some of the heat from the heating elements passes directly to the clothes by radiation.

In order that the machine will not be damaged by the heat produced by the heaters 35 and 36, it is necessary that the basket 14 be rotating whenever they are energized. If either of the belts 24 and 25 fail, the basket 14, of course, stops rotating since it is then no longer connected to the motor 23. Therefore safety means are provided within the machine whereby the heaters 35 and 36 are de-energized whenever either of the belts fail. The safety means comprise a belt switch 37 which is actuated upon the failure of either belt so as to de-energize the heater relay 38 (Fig. 5) and thereby open the heater circuit. The belt switch 37 is arranged on a pivotally mounted sled 39 which supports the transmission assembly 28. Upon the failure of either of the belts the sled 39 is moved by spring biasing means attached thereto, and this movement results in the operation of the switch 37. The arrangement of the sled 39 and the switch 37 is fully described and claimed in the copending application of Daniel L. Duhamell, In, S. N. 526,413, filed August 4, 1955, and assigned to the same assignee as the present invention.

The means whereby water is admitted to and discharged from the tub 15 during operation of the machine are particularly shown in Fig. 3. The water supply means includes connections 40 and 41 through which hot and cold water are supplied to the machine. For the washing operation a valve controlled by a solenoid 42 admits hot water to the machine and a Valve controlled by an opposed solenoid 43 admits cold water to the machine. The hot and I cold water valves under the control of the solenoids 42 and 43 discharge through a common outlet conduit 44. From the conduit 44 the inlet water passes through a suitable air gap into a funnel 45. The funnel 45 discharges into a line 46 which leads into the interior of the tub 15 through a suitable connection 47 (see Fig. 4). The break or air gap provided by funnel 45 makes it impossible for water to be siphoned from the machine to contaminate the incoming water supply line. In the illustrated machine a pressure actuated sensing device or water level control 48 controls both the water solenoids as'reg-saaa 42 and 43' tomaintain theproper watex level 'in the-mat chine during-the washingoperation. This sensing'deviee issconne'cted to the interior'of tub by asuitab1eline49'l The illustrated mach-ine is of the type which uses cold waterduring the di yingeycl -fop condensing the moisture extracted from the wet clothes. This condenser water-"is admitted: to the machine through an additional" solenoid actuated val ve controlled bya= solenoid50 l(Fig: 3) The solenoid- 50 is energized-:3during-the drying' operation so the valve passeswater at a slow rate'suificient' to condense themoistu're' extracted from the clothesl As. shown, the condenser water valve discharges into the funnel" 45 through a separate conduit SIL A-n air gap between conduit 5 1 'andt-he funnel prevents supply line contamination. From the funnel the condenser Water flows through line 46 :and'conncctiom 47 into the tub. The condenserwater flowing slowly" into the t'u b is spread o'ver the side of the tub by an invertedv-sha'p'ed bead 52:(Fig; 4) formed on thetu'brwal-ldireetlybelhw'conneetion 47. The condenser water' 'being sospread outcools a substantial portion of the area of the side wallwhereby there isprovided a large' 'cool surface for condensing the'moisture extracted from the clothes The wash}: and rinsewater used during the washing portion of the operation and the condenser water and the moisture extractedfrom" the clothes during the drying operationiare discharged from the machine through a sump 53 mounted "at the" bottomiof the tub'; A suitable dischargehbse 54 leads-from--the fittingto a motordriven" drain pump-55" which discharges to the householddraiii; The flow through the discharge line may; however, bacon trolled: by any suitable means; as for example; by-a solenoid actuated drainvalve;

Referring now to the schematic circuit di'agramof Fig, 5, there"is sh'owntherein a control syste'm for the com' binatiorr washer and dryer which embodies our inventionincon'c preferred form thereofl Thee onti-ol system in eludes a timer operated sequence control mechanism gen= erally indicated: at 56" anda single level thermostat 57. ThewthermOstatSTis actuated by mean'sof a sensing bulb 57a: within the tn b l f to which it is connected by means of a hydraulic line 57 (Fig; 3). The sensing bulb. 57a comprises. a generally U-shaped member which is positioned: in 1 the air gap between the side wallof the tub and the'iouter surface of the basket. Positioned inthe air gap therbulbsensesa temperature during thedryiiig cycle which is correlated with the temperature ofthe clothes within the basket. The temperature at the thermostat bulb I is higher than the clothing temperature but it rises and falls'with the clothing temperaturesothatit can be used as an" indication thereof.

The thermostat 57 has a normal position and atripped position and in itsnor mal position 'it closes one setof'contacts 59 andopens a second set of contacts 60; whereas in its tripped position itclosescontac'ts 60and opens the contacts 59. In other words it includes a normallyclose'd' set of. contacts 59- andanor1nallyopen setof contacts" 60'.

- temperature within thetub and it resets at a predetermined lower tempertaure so as to open the contacts 60 and reclose the contacts 59. shown) may beincluded within the thermostatsovas to allow some operatorselection: of the trip andaresctting temperatures: The thermostat 5'7 is particularly used. in our control system to control the heaters 35 and 36 during, thedrying operation and alsoto control the lengthof the operation itself:

The sequence control meehanism'fitiis utilizedin"conjunction. with the l thermostat during the drying operation and it independently centreis the machine" duringwhe" Suitable biasing. means (not.

washing operatienz" The sequencecon'trol mechanism. is operatedby meansof a suitable tinrermot0r62 and it ineludes a series' -of switches 63 through 74 which are actuated 1 in the desired sequence by, appropriate switch operating means driven by the timer and indicated schematieally bythe dihgranr75f Sequence: controls generally are well known, and several types are commercially available: Therefereg therepresentation ofPig; 5.iS purely schematic; if being understood; however,. that each of the switches 63'7'4*- is*op'eratedfrom its normally open position to its-closedpositionby-means such as cams. In the particular*representation of FigLS it is to be understood thateach switelhisconnected to' an" actuating means as indi'c'ate'dby the dot dashlines; the switches being closed during the periods indicatedbytheheavy' black lines on the cam diagramt For example; switch 63 is actuated to it's'elosed po'sition'on'the diagram from'points 11 to 23. A

shows the l ength of the impulses'givento advance the camsin. the forward 'rotational direction. In other words, the ch'art TS may beWega'rded for the purposes of this application'tobe'a development of theperiphcries of the respective switeh operating earns; the heavy lines showing the cam rises' which are effective to close respective switches? Fiirtherit will-be understood that the timer camsareprefrabljtjdi iven with an impulse or intermittent motion by means of asuitable mechanism (not shown) connectedlfbetwe'en them and the timer motor. Thus at switchoverpoints-where-the chart 75 shows one switch opening' and another closing; there isaouick make and break action so that one switch is closed simultaneously as 1 the other opened;

Further details withre'spect to, and the operation of our new and-e irnproved control system will become apparent by a review of a typical sequence" of operation. Since our invention is particularly directed to the control of the dryingoperation; the drying operation will be explained first. Itwill be'understood; however; that normally the drying operationwill be preceded by and will follow automatical- 13/ the Washing-operation: Referring to the chart-75 it will be' see'n that the dryingfoperation begins at the point 27 of the scale and that atthat point the switches 65, 6'7, 68, 69} 7l' a'nd 74 of the sequence control are closed. The remaining;switchesof" tho-control are open. With these switches closed both the heating elements 35 and 36, the drive motor 28, the condenser water valve solenoid 59, the drainpum-p SS'Tand-the timermotor 62 are allenergized. Thepower for energ'izing these elements is supplied from a three wirepower source comprising power supply lines 76'and 7'7 and an'electrieal neutral line73i. This three wire-source may for example comprise the conventional 23Olvolt' domestic supply, having a voltage of 230 volts between thesupplydines 76 and 77 and a voltage of 115 volts between each of the power supply lines and the neutral. line -78.

With the above mentioned switches closed, the drive motor 28*is energized-across the supply conductor 76 and.

the neutral line78i' Commencing'with the conductor '76,

thedtivemotor circuit extends through the main oif switch 7 and a door operated switch 79 to a conductor 86. The door operated switch 79 comprises a safety switch which is closed Wheneverthe. door 5 is closed and which isopenedautomatically whenever the door is open, and being'connceted serially in the motor circuit it, of course, intermptsmotor. rotation whenever the door 5 is open. From the conductor 80 the motor circuit continues throughthe omit dry switch 10, which is closed since it is desired to'eonducta drying operation, tot the switch 65 of'the sequence control. From theclosed switch 65 the circuit passes through a: conductor 81 to the lower contact 82.1of'the waterlevel switchL48. Since thereis little ornowaterin the tub 15; the lower contact 82 is engaged by thecenter movable contact83 of theswitch .so that a circuit iseompleted therethroughL However, if the machine should become flooded i. e. should become partially filled with water, the contact 83 will be actuated so as to disengage the contact 82 and close with the upper contact 84 of the switch. This breaks the motor circuit and interrupts the rotation of the tumbling basket. The water level switch thus acts as a flood switch during the drying operation.

From the contact 83 of the water level switch the motor circuit continues through conductors 85, 86, and 87 to the start and run windings 88 and 89 of the motor. The motor circuit is completed from windings 88 and 89 by means of a conductor 90 which is connected to the neutral line 78. The run winding 89 is connected directly to the conductor 90 and the start winding 88 is connected thereto through the contacts 91 of a motor Centrifugal switch 92. When the motor 23 is at rest the contacts 91 are closed but as soon as the motor comes up to speed, the switch opens the contacts 91 so that the motor operates the main winding 89 alone.

Energized through this circuit the motor 23 is efiective to drive the basket 14 until such time as any one of the timer operated switch 65, the door switch 79 or the main switch '7 is opened. Flooding of the machine will also interrupt the motor rotation by the opening of the contacts $2 and 83 of the water level switch 48. During the drying operation the basket should, of course, be driven at tumble speed and not at centrifugal extraction speed and for that reason the shift solenoid 32 is de-energized. Specifically, the sequence control switch 73 is open which breaks the circuit for the shift solenoid 32 and thereby causes the transmission to be set at its tumbling speed ratio.

Both heaters 35 and 36 are initiated at the beginning of the drying cycle in order to apply maximum heat to the clothes as they are tumbled. In order to energize the heaters the heater relay 38 is energized by means of the sequence control switch 69 so as to close the relay contacts or switches 93 and 94. The heater relay 38 specifically is energized by a circuit between the supply conductor 76 and the neutral line 78. From the supply conductor 76 to the conductor 87 the circuit is the same as the drive motor circuit. From the line 87 the relay circuit continues through the sequence control switch 68 and conductors 96, 9'7 and 98 to the switch 69. From the switch 69 the circuit passes through the conductor 99, the belt switch 37 and the conductor 100 to the relay 38 itself. From the relay the circuit is completed through conductor 101, the contacts 102 of the motor centrifugal switch 92 and the conductor 90 to the neutral 78. The contacts 102 comprise a set of back contacts in the motor centrifugal switch and are closed whenever the drive motor is up to speed.

With the heater relay energized through this circuit the relay contacts 93 and 94 are both closed for energizing the heaters. The heaters comprise 230 volt heating elements and they are energized between the two supply conductors 76 and 77. Commencing with the supply conductors 76 the heater circuit extends through conductort 103 and relay switch 93 to a safety thermostat 184. The safety thermostat includes a pair of contacts 185' and 186 and so long as the temperature within the machine is at a safe temperature for the clothes being tumbled, the movable element of the safety thermostat is closed against the contact 105. However, if an overtemperature condition should occur the movable element closes against the contact 106. Assuming the temperature within the machine to be at a safe value, the heater circuit is continued from the contact 105 through a line 187 to the normally closed contacts 59 of the thermostat 57. The contacts 59 are closed until such time as the temperature within the machine rises far enough to trip the thermostat 57. The selection of this trip temperature will be explained hereinafter. From the contacts 59 the heater circuit passes through a conductor 108 directly to the heating element 35. However, it passes to the heating element 36 through the switch 74 of the sequence control mechanism. The sequence control switch 74 is connected to the conductor 108 by a line 109 and is in turn connected to the heater 36 through another line 110. From the heaters 35 and 36 the circuit is completed through the heater relay contacts 94. Energized through this circuit it will be seen that both heaters will be energized together until such time as the thermostat 57 trips and opens the contacts 59. At that time both heating elements will be de-energized simultaneously. As will be explained later our control system is so arranged that the sequence control switch 74 never opens before the thermostat trips.

'In order to condense the moisture extracted from the clothes by the heating elements 35 and 36 the condenser water solenoid is also energized at the beginning of the drying operation. The energization of the condenser water solenoid of course opens the condenser water valve and passes a steady flow of condenser water into the tub 15 through the funnel 45, the conduit 46 and the fitting 47. This condenser water entering the tub is spread out by the inverted V-bead 52 and flows down the side wall of the tub in a thin film or sheet so as to cool the side wall and condense the moisture extracted from the clothes. The condenser water solenoid 50 like the drive motor is energized across the conductor 76 and the neutral line 78. The circuit is the same as the drive motor circuit to the line 87 and from the line 87 the condenser water solenoid is energized through the sequence control switches 68 and 67. Commencing with the line 87 the condenser water solenoid is energized by a circuit through the switch 68 and connections 96, 97 and 98 to the solenoid 50 itself. From the solenoid the circuit is completed through conductor 111, timer operated switch 67, conductors 112 and 101, the back contacts 102 of the motor centrifugal switch 92 and the conductor 90 to the neutral line 78. Energized through this circuit the condenser water valve remains in operation so long as the timer operated switches 65, 67 and 68 are closed and so long as the motor continues in operation. If the machine should be flooded, the drive motor will be de-energized by the water level control 48, and due to the action of the centrifugal switch 92, this will result in the deenergization of the solenoid 50 and the stoppage of the flow of condenser water. The opening of the timer operated switch 65, of course, will de-energize the condenser water valve at the same time as it ultimately de-energizes the drive motor.

Incidentally, it will be noted that a lamp 113 is connected in parallel with the condenser water solenoid 50 so that it is energized whenever the solenoid is energized. This lamp 113 acts as a visual indicator to show that the drying operation is in progress.

The drain pump is also energized during the drying operation in order to discharge the condenser water and the condensed moisture from the machine. The drain pump like the drive motor and the condenser water valve is energized through the switch of the sequence control. Commencing with the closed switch 65, the circuit for the drain pump extends through conductor 81 to the water level switch and thence through the contacts 82 and 83 of the switch and conductor to conductor 86. Conductor 86 leads directly to the drain pump 55 itself and from the drain pump the circuit is completed through conductor 111, timer operated switch 67, conductors 112 and 101, contacts 102 of the motor centrifugal switch and conductor to the neutral line 78. Energized through this circuit the drain pump remains in operation so long as the sequence control switches 65 and 67 are closed, and so long as the drive motor continues in operation. If the drive motor should cease running the drain pump will, of course, be de-energized by the centrifugal switch at the same time as the heaters and the condenser water valve.

At the beginning of the drying operation the timer motor 62 is also energized between the power supply 75 sesame,

and. the neutral; line: 78rso as] to: advance the operating. cams i. of 1 the: sequencercontroll mechanisms Specifically, the timer 62,1 iszene'rgizederthrn ugh thezsame circuit as: the drive/motor. to". the conductor? 87.. and.from thereit is energized: through. the. sequence: control switclr 72. The switch 72Jis' closed at .therbeginningzof. th'e drying operati'oncasz shownbin. the chart 75 an'd frlomi it thettimer circnitn continues through thevconductorszll l and 115 to': thertimer motor 62litself.. Fr'orn= thertimer motorthe. circuitisa completed.ithrouglrconductors'116and 90 to thevneutralzline;78l Energizedflin thisrnanner the timer motor: continues. to run' until? suchctime as. the; switch 72 opens;

Referring-to the: cam chartfit will" be-seenvthat the timer switchu72 remainsmclosed only-briefly after the washer-'dryer'proceeds into thedrying cycle. Specifically, the;switch. 172' remains-closed energizing the timer motor longgenoughsfortthe. timer motor: towclose all. the other switches for the dryingjcycle i. ea, long enoughtfor it tor'clo'sel the-switches 68; .69 and 2 74, the: switches 65 and 6 7ubeingialready closed. Then the: timer'switch 72: opens up de-energizingthetimer motors Withthetimer motor de-energized the:contro1 of the. heatingpelement and of the machineritself is their placed undertthe action of the thermostat 57.

During. this initial periodwthe-heating elements'35 and 36 arer, of course,both energized to supply maxi-mum wattage for'heat-ing' the clothes Thesize' of the heaters will dependxupon'theparticular machine constructed, but in; a size of .the' illustrated washer-dryer? suitable for domestic use having a clothes? basket twenty-six. (26) inches in diameter it. haswbeen' foundthat. at-otal power ofr -fourthousand (4,000.) watts from: the two heating" units provides-a. satisfactory amount ofxheat. forxmoisture.

extraction during thefirst stages ofifth'e. drying operation.

A total of 4,000 watts extracts moisture: from the clothes alsatisfactory rate without overheating the tub or any othenportiom. of the machine. For reasons explained below: the'si-zevof the heaters: is apportioned in this exemplary' machine so that the one" heaterfit'sisapproximately a twen-ty-eight hundred. (2,800) watt heater and the other heater: 36' isapproximately a; twelve hundred (1,200) watt heater.

Both. heaters 35 and 36 remained energized applying maximum: heat; to the clothes. until'such" time as the machine heats up farenough to causethe thermostat 57' toatripp During thisperiod. of maximum: heater power application the machine: heats up slowly at first as the In fact, for a moisture is extracted from the: clothes; timellt-he heat supplied may be approximately equal to the heat iused for moisture extraction or evaporation and in:

that case aplateau may" even occur in the curve of the temperaturerise. However, once all the surface moisture is. evaporated from the clothes; thermachine thenibcgins to heat up rapidly. After the surface moisture has been removed, themaximum wattage availablefrom' the two heaters, for: example 4,000 watts, is more than can be In other wordsall' of the 4,000 watts, once the surfacemoisused to: extract'the moisture contained in the fibers.

ture has-been removed, does not cause evaporation'ot the moisture'from the fibers. R'ath'eronly a portion of this power can be used for the evaporation of the moisture from thefibers since it will "only evaporate at a certain maximum rate no matter how inuchtpower isapplied within reasonable-limits. The fabricscandeliver moisture by 'capillary action from the interior of the material to the from-:theheaters thereby causes the machine to heatup natherrapidly'.

The trip p'oinflfor"the 'thermostat 57 is selected at a temperature slightly above where this-rapid rise begin-s to occurl As=a-result when the machine is heated up to- 10 thetrippoint forthe first tim'e, allof the surface moisture from the clothes has been: removed but" there is still remaining 1 within the fibers of the clothesan appreciable amount of moisture. The heat has not been applied long enough after the surface: moisture'is removed to evapo rate all of the moisture contained within theiibers'. However, to continue: the heating with both heaters energized for a longer period of time would result in overheating of the machine andthe clothes: sothat even scorching of the clothes might result.

The trip point thus is selected at a-temperature slightly above that at which the surface moistureis allrernoved from the clothes. Forexample, intheillustrated machine it is contemplated that the thermostat will'trip at 230 F. when a normal load of clothes is' being dried, that is, a load substantially comprise'd' of cotton materials. For a load of heavy fabrics such as'shagrugsand dungarees the trip point may beselectedslightly higher since there is-more moisture-to be extracted from the fibers and since T they may be heated to a slightly higher temperature higher than the clothes temperature, as was mentioned above.

When the thermostat 57 trips'from'its normal position to its tripped position, the thermostat contacts 59' are opened and the contacts 60 are closed. The opening of the contacts 59' breaks the heater circuit so that both heaters 35'and 36 are de-energi'zed. Thereby the machine immediately starts to cool down; The simultaneous closing of the contacts 60, however, energizes the timer motor 62 so that it begins to operate again. Specifically, with the contacts 60 closed, the timermotor is again energized between the supply conductor 76 and the neutral line 78. Commencing with the conductor 76 the timer motor circuit extends through conductor 103, relay switch 93, the safety thermostat 104, conductor 107, and the now closed thermostat contacts 60 to a conductor 117. The conductor 117 is connected to the conductor 114 and from there the circuit is completed to the timer motor through the conductor 115. From the timer motor itself the circuit extends to theneutral line 78 through the conductors 116 and Energized through this circuit the timer motor begins to drive the sequence control mechanism toward the off position. Shortly afterit begins to run, i. e. at point 23 of the scale of the cam chart 75, the timer causes the switch 72 of the sequence mechanism to close. This locks in the timer and continues it in operation even if the thermostat should reset immediately"thereafter. Simultaneously, as it closes the switch 72' or slightly thereafter thetimer causes the sequence mechanism to open the switch 74. The opening ofthe switch '74 breaks the circuit to the heating element 36 whereby the heater 36 cannot be reenergized when the heater circuit is reclosed through the thermostat. After the switch 7 5 is open, the sequence control mechanism then continues to operate for" a period of time, forexarnple, to a point slightly beyond'the point 30on' the cam chart and at that point the switch 72 is again opened. Theopening of the switch 72' again breaksthe timer motor circuit so" that the timer motor iS compIeteIy de-energized and the sequence control remains at a standstill.

During this operation of' the sequence control motor the machine is continually cooling down'dne to the de-energizatiotr of the-heating elements. Atapred eterminedtem- V perture belowthe trip temperature. the cooling down of the machine results inaresettingof the thermostat 57.

In other words at that temperature the thermostat returns to its original or normal position reclosing the contacts 59 and opening the contacts 66. The closing of the contacts 59 completes the heater circuit again but now only the heating element 35 and not the heating element 36 is energized. The above mentioned opening of the sequence control switch 74 has removed the heating element 36 from the circuit. Thus in the above mentioned exemplary machine only 2,800 watts and not 4,000 watts are now applied to the clothes for the evaporation of the remaining moisture contained within the fibEIS.

With the single heater 35 energized the drying opera tion continues at a very slow rate of rise or perhaps even with a temperature plateau. The heat supplied from the single heating element is for the average size load of clothes approximately equal to the maximum wattage which can be utilized to extract moisture from the fibers. in other words heat is supplied from the single heating element at approximately the maximum rate which can be used for moisture evaporation from the fabrics. Thus there is not a rapid heating up of the machine although the temperature does rise slowly. This drying action continues until the trip point of the thermostat 57 is reached a second time. Normally the clothes are substantially dry when this temperature is reached. They may not be completely dry, that is all the possible moisture may not be removed from them at that time, but a complete removal of the moisture is not necessary for satisfactory drying. In fact, to prevent damage to the clothes it is desirable that a slight amount of moisture may even remain in them, for example an amount of moisture equal to approximately of the dry weight of the clothes. Thus it is contemplated that the trip point he so selected that the clothes will normally contain this 5% moisture content. when the trip point is reached. It will be noted, however, that if all of the moisture should be removed from the clothes before the trip point is reached, the machine will then heat up very rapidly to the trip point and the heater 35 will be deenergized before any substantial overheating and damaging of the clothes can result.

The tripping of the thermostat 57 for the second time again opens the contacts 59 and closes the contacts 6%. The opening of the contacts 59, of course, de-energizes the heating element 35 and the closing of the contacts (at) re-energizes the timer motor 62. The timer motor again begins to drive the timer mechanism toward the oif position of the washer-dryer. Shortly after the timer motor again goes into operation, the sequence control switch 72 is closed so as to lock in the timer circuit. Simultaneously with or slightly after the closing of the switch 72, the switch 69 is opened. This opens the circult to the heater relay Stl whereby the relay switches 93 and 94 in the heater circuit are opened. Thus even if the thermostat should reset, the heater circuit can not be reclosed.

The machine continues in operation with the heaters off with the timer motor running so as to provide a cool-down period. In other words the drive motor continues to operate the basket 14 for a timed period with the heaters off so as to allow a cooling of the machine to a suitable temperature for the removal of the clothes. Ultimately at the point marked Off on the cam chart the timer mechanism opens the switch 65. The opening of the switch 65 de-energizes all of the elements of the control including the timer motor, the drive motor, the drain pump and the condenser water solenoid and thereby it completely terminates the operation of the machine. The dry clothes may then be removed by the operator.

From the above it will be seen that we have provided a new and improved dryer control in which a single level thermostat is used both to control the heaters and to determine the length of the drying operation. As a result of the operation of the single level thermostat in conjunction with the sequence control mechanism, both heaters are initially energized to apply maximum wattage to the clothes until the surface moisture has been removed therefrorn. At that time both heaters are deenergized so as to allow the machine to cool down slightly. When the thermostat resets then only one heater is returned to operation so as to extract the internal moisture from the fibers of the fabrics. This is done, of course, since both heaters supply more than enough heat than can be used for the extraction of the internal moisture. When the trip point of the thermostat is reached a second time under the heat supplied from the single heating element alone, the internal moisture of the fabrics has been substantially removed. At that point the sequence control mechanism is again energized so as to completely break the heater circuit, and then after a suitable cooldown period the operation of the machine is terminated. By this use of a single level thermostat a relatively inexpensive and simple control arrangement is povided. Also it results in the total wattage being applied during the earlier portion of the drying operation for the maximum possible time. Thus a shorter drying operation is provided than has heretofore been possible.

It will be obvious that the thermostat differential between its trip point and its resetting point is important to the functioning of the control. If the di 'erential is too large, the thermostat will not have reset to reclose the contacts 59 and open the contacts 60 before switch 72 is opened by the timer shortly after point 30 of the cam chart. Unless the thermostat has reset by that time, the opening of switch 72 would not turn off the timer, rather it would still be energized through contacts 60 so it would continue to run. Thereby it would first open switch 72 and then shortly thereafter reclose it. Once switch 72 is reclosed the timer is then, of course, energized continuously from slightly before point 31 on the cam chart to the off position to time out the operation no matter what the thermostat does. This would means the drying cycle would be quickly turned off without the reduced power operation taking place at all. Thus in order to obtain the reduced heat operation of the cycle, the thermostat must reset before switch 72 is opened. In other words it must regain control by that time.

In our preferred embodiment using a 230 F. trip point, we arrange the thermostat so that it resets about 20 below the trip point, plus or minus 5. With the differential the thermostat ordinarily resets before point 30 on the cam chart is reached and thereby the second or reduced power period of heating is assured.

If the thermostat does not reset at this differential, it is normally because the clothes are already dry and do not need the second or reduced power period of heating. For example, a load composed of delicate synthetic fabrics may, unlike the heavier loads, be substantially dry when the thermostat trips the first time. Being substantially dry they are giving of]? little vapor or moisture whereby there is poor heat transfer within the machine. As a result the machine does not cool down so rapidly when the heaters are turned oil. Thus, the thermostat does not reset until switch 72 has been reclosed at point 31, and the timer times the machine out. This is, of course, desirable because to apply more heat to the synthetic fabrics might result in over-drying. Thus our preferred differential not only assures that the reduced power operation will occur for those loads which need it, but also prevents it from occurring for these loads which do not. Of course, if the thermostat differential is too small, then the reduced heat operation would be effected for all loads, even for those delicate fabric loads which do not need it.

With regard to the safety features available during the drying operation, it will be noted that if either of the drive belts 24 or 25 should break, the belt switch 37 immediately opens the circuit to the heater relay and com-- pletes a circuit for driving the timer motor to the of position... Specifically Mlle: belt .swi-tcha breaker the.;'heater relawcircuit between the. conductors: 99 and; 100J'and.jlCQm7 plates. at timerrmotor circuithy connecting theconductor 99.to: the"conductor 115. Energized-through thisicircuit; the timer motorwill. run continuously until-.-.suchltirne. as the control switch 72 closeswtor SECOl'ldItliIlG4: The timer then. continues. in operation through thatswitch until it... opens .the. switch 65' to. deaenergize. all. the operating elements. of the machine. Thus it will. be. seen thatrifi either belt should break, therheaters zare .deaenergizediandthe. timer is caused torun 'continuously untilthe machine is...finally+shut off.

Iithemachine. should-become flooded, the. heaterwrelay circuitis likewise. broken and the. timer motor-energized. A150,. the. drivemotor, the. condenser. water valve 1and-the drain pump are (is-energized. Ifiitheamachinerbecomes floodedthewater levelzswitch. 48 --opens .the contacts. 82 and-83 rand. closesathe: 'contactsr83 and- .84.. The. opening of the contacts -82.- and 83. breaks the heater relay circuit the drive: motor circuit, the condenser water. solenoid circuits L and. the.v drain: pump circuit. The. closing of ithe. contacts. 8.3 and. 84*,- however, energizes? the timenmotor. through. conductor. 1 17, .switch-;7.1.. ofi thexsequence .con:- trol and conductor- 115: The: switch 71*1ofr-thG sequence: control. is-so c arranged thatritaremainss closeduntil such. time as; thelsequence control. switch. 72-.closes fr the1 seoondttimer Thenifi theqmachineiis stillsflooded. the. timerimotor shuts off .too; conversely if the. flood-i cone-- dit-ionrhaszcleared p; the machinewill then'. be timed. cutthroughthe. cool-down PBI'iOdl.

If the' machine shouldroverheat duringt-hevdnyingopr. erationathe safety thermostat. will. be: tripped sooas to: closethe conductor 1tl3-to theroontact.lflfir rather thani tot'the contact ltls. Thisu ofcourse, resultsin. the heater circuit. -1 being broken and further it energizes. the; timer motor through the conductors .117' and 1-15. Thus so. long; as the? over-temperature. conditions continues.. the. heaters: arcade-energized .andot-he timer: motor-.is iin operatiOH SGw' as toiidrive: the sequence controlr mechanisnntowandithe! oft f position To! complete? the? description. oil. the controhsystemof. Fig. 5 we willanow. .explainahowiticonducts..theamachine. through. the washing operation. prior to conducting. it. through. the drying,operationndescribed. above... For that. purpose, lets it. i be assumed. initially that: the... sequence. control isvset inthe. space just. preceding. zero. on. the scalev ofirtlt'ecam chart,,.that.is,.-in.the. oihi position. Letwit. also bewassumed that main. switch. 7 is..manuallyclosed. andothat. the. door switch. .79 is closed... While: cams. actua ated. switches 67,.6d and 72..are.. closed, no. powenisrsup p liedato anyof. the. electrical. componentsof. thepwasherdryer from .power. supply lines 76.. and -77 and. neutral. line-. 78a. To initiate thewashingaoperationz.thesequencecontrol is non/manually advanced. tora position-slightly. bGYOHdLZQIO. As a result cam actuated 1switches.6.'7',.68 and 72 are opened while switches 64; 616;, 70 71and-74 areclosed. Closure ofswitch 66..completes...a.circuit to-.,-main.drive motor 28.;commencinggwithline 76..and. extending-through the main switch 7. and.door.switch79. to':lii1e8.0;1 From: linethecircuit.continues-through. switch 6610"[116 conductor SGZcQnnectedi-tcr the drive motor; and from the drive. motor it. is. completed to new trall'line. 76'through conductor. 90. Inlthis manner clo sure=rof the switch 66 causesoperation of themain drivemotorrthroughout the period ofwopera-tion: of. the. apparatus-1 as ac-:washing.machine. The. starting; Winding. 88 of' the=motor, of course, remains inthe circuit only until motoir'comes up to speed; whereupon it-isdisconnected: blytheznrotor centrifugal switch 92.

Simultaneously with the; energization. oi the drive-moms anzaut'omatic water. fill. control is: energizedthroughcam; actuated switch 66; Thisfill contro'lccomprises the water: va'lve' solenoids 42 and 43 and thewater :level switch 48: Tlle circuit for energizing the 'watenvalve solenoids may? betraced through the :mainewitchfl; door switehaw, line stt-andtcamt aetuatedvswitchzoo to: the: linesvfife. and 86 leadingq-tocontact 83 of the: water. level. switch assembly; 43; Asrmentioned above, contact 83: is. normally closed? with contact 82 when thereis no liquidtin the machinegubut as thesliquid rises the hydro-static: actuating;means rises,.liftingcontaetSfi clear of contact 82 and closing it withcontact 84: Thus when the machine. is empty a: circuit. is completed:* through the water. level switch to the line 81. connected at the contact 82. The line ulnleads to a conductor IIS- andthe:conductor 118 is connected to one terminal of. the hot water control solenoid42. The opposite-terminal of the hot water sole:- noid is connected. through a line? 119" to i camwactuated switch 64, which" when. closed, completes; acircuit. to *line 129. Line120 is connectedto thexelectricali neutral. 78 through conductor 101, the normally open contrctsxltli. of: the centrifugal switchwand conductor 9d to complete the water valve circuit. Fromthiscircuit it may be seen that the energization of .the water valve". solenoidmiznis dependennfirstupon closure: of actuated switch 66;. secondly; upon the closure oflcontacts and: 83 of thexwater levels-switch indicatingv that. the machine does not. have normal. liquid level; thirdlyupon closureofi cam' actuated switch 64; and-: finally upon closure of'contacts 192.01 the motor centrifugal switch indicatingthatithe' machine is'operatin'g. at normal speed. It will also he noted that coldwater: valve solenoid 43 may be energized .simule taneously with the hotwater valve solenoid 42iby closure ofthe manual warm water switch9-f Switch 91mm.- pletes a circuit. from; line-118 to a liuellZl which is con-. nected to: oneside of the cold watenvalve solenoiduz43. The opposite terminalnot thesolenoidddsislconnectedivto line 119, and thus closure of manual switch. iwenergiaes both hot and cold waterval-ve solenoids in. electrical par; allelto supply warm water to the machine.

The: timer motor 62. unlike thedriveniotordoesnnot begin to rotate .as soon as the control is turned; onf rather the timer motor 62. does not. commence; operation to advance the sequence: control untilnsuch' time as the: machine. has been filled to normal. operating level. As the liquid: level in the machine'riseswater level: controlmeans 48 closes contacts 83 and 84 whennormalnliquid' level is achieved. A timer circuit is then :completed from line through" cam switch 66, lines 86:and 35.; and contacts 83 and 84 ofthewater level switch to the. line 117. The line 117 is connected through cam actuiated switch .71 to line 115,. andline is, of course; connected to one of the terminals of timer motorsdfls The timer circuit is completed fromthe: opposite terminal: of the timer motor to the electrical neutral. '78 through lines 116and 9L".

Inthe illustrated machine the heaters 35 and36 serve asta means for maintaining and. increasing the temperature of the Washing liquid as well. as a means for. evap crating moisture during the drying cycle. While these: heaters, being mounted within the upper portion ofthe tub, as shown by Fig. 4, are not immersed in theliquid in the machine, there is a substantial heattransferfrom: the heater to the rotating basket 14.. Since'the: basket? dips into the liquid as it rotates, and. since'a convective current is created, an effective.- heat transfer means is provided between the electrical. heating elements and the washing liquid. Operation of the electrical heating; elements for maintaining and increasing. the liquid temperature is under the control of the manual heater switch 11 and cam actuated switch 70. caution, this control system is arranged so-thatthewater heating. means cannot be energized unless the machinecontains normal operating level of liquid, unless. both drive belts: areoperative and unless the main. drive. motor is; rotating. at normal speed.

The: heaters are energized by means of the relay 38 which is'eflective the samepas in. the:drying operation to close switches 93 and 94. Heatingelement. 35 is..energized;.through the: relay switchesby" the same-circuitas However, as a safety prein the drying operation, the circuit commencing with line 76 and extending through line 103, switch 93, safety thermostat 1M and line 197 to contacts 59 of the thermostat 57. From the normally closed contacts 59 the circuit passes through line 108 to heating element 35, and it is completed through relay switch 94 to line 76. The other heating element 36 is energized through the same circuit to line 103 and then through line 169, sequence control switch 74, and line 110 to the heating element itself. From heater 36 the circuit is completed through relay switch 94 to the other side of the line. Thus, when relay switches 93 and 94 are closed, both sections 35 and 36 of the heating assembly are energized in electric parallel, assuming the safety thermostat 1M and the dryer control thermostat 57 are both relatively cool and hence in circuit closed positions.

From the standpoint of the control system, the water heating means are energized by applying power to the terminals of the operating coil of relay 38. This is accomplished by a circuit commencing with line 75 and extending through main switch 7, door switch 78, line 80, cam actuated switch 66, lines 86 and 85, contacts 83 and 84 of the water level switch, line 117, the manual water heater switch 11, cam actuated switch 70, line 99, belt switch 37 and line 1069 to one terminal of relay 38. The opposite terminal of the relay is connected to line 101 which completes the circuit to the electrical neutral 78 through the centrifugal switch 162 in the main motor and line 94}. It is thus seen that operation of the water heating means depends not only upon closure of the main switch and the door switch, but also of the water level switch, the manual water heater control switch, the cam operated switch for the heater control, the belt switch, the contacts of the heater relay, and the safety thermostat. As shown, cam actuated switch '70 remains closed for water heating to the first seven intervals as shown by cam chart 75. During this period of the washing operation the heating capacity is sufiicient actually to increase the temperature of the washing liquid. This is desirable in many applications either to conserve the supply of the domestic hot water, or to supplement the heating capacity of the domestic hot water system. During the latter portion of the washing operation, the heaters are cycled on and off for short periods in a manner calculated to maintain substantially the same water temperature; or in other words, sufiicient heat is imparted to the wash water to compensate for thermal losses. At all times, of course, the operator may control operation of the water heater by means of manual heater switch 11.

As previously described, timer motor 62 advances the sequence control during the wash cycle commencing with that moment when the wash water level switch signals that there is normal liquid level within the machine. At point 11 on the cam chart scale, the wash period terminates, and the spent wash water is discharged from the machine by the drain pump 55. The drain pump specifically is energized under the control of cam operated switch 67. When switch 67 closes the pump is energized by a circuit from line 8h through cam operated switch 66, line 86, the pump itself, line 1111, cam actuated switch 67, lines 112 and 101, the motor centrifugal switch and line 9% to the electrical neutral.

It may be noted also that slightly prior to the closure of cam switch 67 for pump operation, cam operating switch 72 closes in order to maintain the sequence control timer motor in operation regardless of the position of the water level switch 4-3. This is essential, of course, since otherwise the timer motor would cease operation Whenever the liquid is drained from the machine. This auxiliary timer motor circuit may be traced from lines 76 and line through cam switch 66, line 87, cam actuated switch 72 and lines 114 and 115 to the timer motor, and thence to the neutral line as previously described.

Concurrent with the energization of drain pump 55, cam actuated switch 63 is closed preparatory to the filling operation for the first rinse. Since it is adequate for the rinsing operations to have a mixture of half hot and half cold water, cam actuated switch 63 functions to connect both water valve solenoids in electrical parallel during rinse fill. Switch 63, as shown, is connected across the manual switch 9 for that purpose.

Upon conclusion of the drain period, cam actuated switch 63 closes to initiate the fill operation for the first rinse in a manner previously described in connection with the initial Washing fill. Cam actuated switch 72 is open, while cam actuated switch 71 is again closed so that further operation of the timer motor is again dependent upon closure of contacts 83 and 84 of the water level switch when normal liquid level exists within the machine. These circuits likewise were described in conjunction with the initial fill for the Wash period.

Following the first rinse, which is completed at point 14 on the cam chart time scale, the first rinse water is drained from the machine by energizing the drain pump 55 through cam actuated switch 67 as previously described. Again, cam actuated switch 71 opens while cam actuated switch 72 closes to continue the sequence control drive in operation in spite of the opening of the circuit through contacts 83 and 84 of the water level control when water is drained from the machine. Adequate'time is provided by the sequence control from points 14 to 15 on the cam chart scale for the water to be pumped from the machine. At point 15 on the scale, cam actuated switch 73 closes to complete a circuit to the spin solenoid 37. Commencing with line 84) this circuit extends through switch 66, line 87 and a movable contact 122 of an unbalance switch 123 to a fixed contact 124. From there, the circuit continues through conductor 125, cam actuated switch 73 and conductor 126 to spin solenoid 32. The opposite terminal of the spin solenoid is connected through conductors 127 and to the electrical neutral 78. The energizing of the spin solenoid through this circuit, of course, shifts the transmission 23 so that basket 14 is driven at high speed to extract water from the clothes.

If by chance the articles of clothing are distributed evenly around the inside of the rotating basket, the machine will rapidly accelerate the basket to centrifugal extraction speed. If, however, due to uneven distribution, vibration of a predetermined amplitude exists, the unbalance switch will be actuated moving contact arm 122 away from contact 124 and into engagement with contact 128. The tub specifically actuates the unbalance.

switch 123 to this result by means of a depending arm 129 (Fig. l) thereon. By the opening of the unbalance switch the solenoid 32 is released, and the machine returns to tumbling speed for re-distribution of the load. Simultaneously, however, from the back contact 128 of the unbalance switch a circuit is completed to an unbalance timer motor 130. The other terminal of this timer motor 130 is connected through a line 131, the motor centrifugal switch and the line 90 to the electrical neutral 7 8. It will thus be seen that upon vibration exceeding a predetermined amplitude, the circuit to the spin solenoid is broken and simultaneously a circuit is completed energizing the unbalance timer motor 130. Thus the machine slows down to allow re-distribution of the clothes and at the same time the unbalance motor 13!? rotates star cam 132. The rotation of the star cam bends leaf spring 133 (Fig. 1) and after a predetermined time interval the spring snaps back resetting the switch 123 to its original position. This resetting of the unbalance switch deenergizes the unbalance timer motor and completes again the circuit of the spin solenoid. The machine then again attemps to accelerate to extraction speed. With this arrangement, it is possible that the machine may attempt acceleration to extraction speed several times before finally attaining a balanced clothes load permitting smooth vibration free performance. But ultimately it will attain that balanced load condition, and severe vibration can never occur since high speed operation is terminated whenever objection 17 able excursion of the tub with the respect to the base occurs.

Throughout the spin period, the sequence timer motor 62 is in operation to advance the sequence control, and, of course, the pump 55 is energized so that liquid extracted from the laundry is discharged to the drain. Upon conclusion of this extraction period, the sequence control switches are again returned to position to cause the machine to refill with rinse liquid and to operate at tumbling speed. The rinse fill and rinse operations are identical with those previously described. Preferably, and as shown on the sequence control chart, a third rinse operation is provided before commencement of the final drain period at point 23 on the scale of the sequence control. This final drain is preparatory to the final spin dry or centrifugal extraction operation immediately preceding the application of heat for the final drying. Throughout the final extraction and drying periods, of course, the sequence control switch 67 is closed,.thereby energizing the pump 55. The centrifugal extraction is controlled, as previously described, by energizing spin solenoid 32 through cam actuated switch 73 and the unbalance switch 123. The sequence control timer remains in operation under the control of sequence control switch 72 in the manner previously described. The final centrifugal extraction periods ends at point 27 on the cam chart when cam actuated switches 66 and 73 open.

If the operator desires to terminate further machine operation, the omit dry button 10 may be depressed, and then when the machine concludes the final extraction period further operation will cease. However, assuming that the omit dry button is not depressed, the machine will go into the final drying period automatically and that period will be conducted as described above so that heat is applied to extract substantially all of the moisture from the articles of clothing. The machine is conducted into the dry period by the switch sequence control switches 65 and 72, the switch 65 closing slightly before the final spin period is ended and the switch 72 being closed throughout the final spin period. After the machine proceeds into the dry period, the energization of the two heaters 35 and 36 and the duration of the drying period itself is controlled by the single level thermostat 57 acting in conjunction with the sequence control mechanism 56 as described above.

Incidently, referring to Fig. it will be noted that the control system includes an indicator light 134 for giving a visual indication of the operation of the machine. This lamp 134 is so connected that it is energized both during the washing and drying operations of the machine and it may, for example, be positioned behind the sequence control dial 12 so as to illuminate it during the machine operation. Specifically, to effect that result the lamp 134 is connected between the line 86 and the neutral line 78. Connected in this manner the lamp is energized through the sequence control switch 66 during the washing operation, and the sequence control switch 65 during the drying operation.

While in accordance with the patent statutes we have described what at present is considered to be the preferred embodiment of our invention, it will be obvious to those skilled in the art that various changes and modifications.

may be made therein without departing from the invention and we, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Clothes drying apparatus comprising clothes tumbling means, a pair of electrical heating units, and a control system comprising a thermostat responsive to the temperature within said apparatus and having a normal position and a tripped position, said thermostat opening to said tripped position at a predeterminedhigh temperature and resetting to said normal position at a predetermined lowertemperature, a sequence control mechanism including a timer and a plurality of switches operated by said timer, and means including said thermostat and said sequence control mechanism for energizing both of said heating elements simultaneously, said elements being arranged to provide heat to said thermostat until said thermostat trips a first time in response to the heat from said elements, said means energizing only one of said elements thereafter upon resetting of said thermostat, said one energized element being arranged to provide heat to said thermostat until it trips a second time, said means deenergizing said one element too and terminating the drying operation when said thermostat trips the second time in response to the heat from said one element alone.

2. Clothes drying apparatus comprising clothes tumbling means, a motor for driving said clothes tumbling means, a pair of electrical heating units, and a control system for said motor and said heating elements, comprising a thermostat responsive to the temperature within said apparatus and having a normal position and a tripped position, said thermostat opening to said tripped position at a predetermined high temperature and resetting to said normal position at a predetermined lower temperature, a sequence control mechanism including a timer and a plurality of switches operated by said timer, means including said thermostat and said sequence control mechanism rorenergizing both of said heating elements simultaneously, said elements being arranged to provide heat to said thermostat until said thermostat trips a first time, said means energizing only one of said elements thereafter upon resetting of said thermostat, said one energized element being arranged to provide heat to said thermostat until it trips a second time, said means de-energizing said one element too when said thermostat trips a second time, and means including said sequence control mechanism for energizing said drive motor throughout the entire operation of the heating elements and for a timed cool-down period thereafter.

3. Clothes drying apparatus comprising clothes tumbling means, a pair of electrical heating elements, and a control system comprising a thermostat responsive to the temperature within said apparatus and having a normally closed set of contracts, said thermostat opening to a tripped position at a predetermined high temperature and resetting to its normal position at a predetermined low temperature, a sequence control mechanism including a timer, heater circuit means for energizing said heating elements, said heater circuit means including said nor mally closed set of thermostat contacts and heater switch means controlled by said sequence control mechanism, with the circuit to one of said heating elements including a first switch operated by said timer, said heater circuit means being arranged to energize both of said heating elements simultaneously until said thermostat trips a first time in response to the heat from both of said elements, and means responsive to the first tripping of said thermo stat for advancing said timer to open said first timer operated switch, thereby to cause said heater circuit means to energize only the second of said heating elements to continue the drying action upon the resetting of said thermostat, and responsive to the second tripping of said thermostat caused by the heat from said second element only for advancing said timer to open said heater switch means, whereby said heater circuit is completely disconnected for terminating the drying operation.

4. Clothes drying apparatus comprising a pair of electrical heating elements, a clothes tumbling drum, a drive motor for driving said clothes tumbling drum, and a control system comprising a thermostat responsive to the temperature within said apparatus and having a normally closed set of contacts, said thermostat opening to a tripped temperature, a sequence control mechanism including a timer, a motor circuit controlled by said sequence control mechanism for energizing said drive motor throughout the drying operation, heater circuit means for energizing said heating elements, said heater circuit means including said normally closed set of thermostat contacts and heater switch means controlled by said sequence control mechanism, with the circuit to one of said heating elements including a first switch operated by said timer, said heater circuit means being arranged to energize both of said heating elements simultaneously until said thermostat trips a first time in response to the heat from both of said elements; and means responsive to the first tripping of said thermostat for advancing said timer to open said first timer operated switch, thereby to cause said heater circuit means to energize only the second of said heating elements to continue the drying operation upon the resetting of said thermostat, and responsive to the second tripping of said thermostat caused by the heat from said second heating element only for advancing said timer to open said heater switch means, and a second switch operated by said timer subsequent to the opening of said heater switch means for de-energizing said motor circuit and terminating the operation of said machine.

5. Clothes drying apparatus com rising clothes tumbling means, a pair of electrical heating elements, and a control system com rising a thermostat responsive to the temperature within said apparatus and opening to a tripped position at a predetermined high temperature and resetting to a normal position at a predetermined lower temperature, said thermostat having a first nor mally closed set of contacts and a second normally o en set of contacts, a sequence control mechanism including ing a timer and a plurality of switches operated by said timer, heater circuit means for energizing said heating elements including said normally closed set of thermo stat contacts and heater switch means controlled by said sequence control mechanism, with the circuit to one of said heating elements including a first one of said timer operated switches, said heater circuit means being'arranged to energize both of said heating elements simultaneously until said thermostat trips a first time in response to the heat from both of said elements, a timer circuit for energizing said timer closed by said normally open set of thermostat contacts when said thermostat is in said tripped position, said timer being arranged to open said first timer operated switch when energized by the first tripping of said thermostat, thereby to cause said heater circuit means to energize only the second of said heating elements and not said one heating element upon the resetting of said thermostat, and said timer being arranged to operate a second of said timer operated switches to open said heater switch means when said timer circuit is again energized by the second tripping of said thermostat res onsive to the heat from said second element alone, thereby to disconnect said heater circuit means and terminate the drying operation.

6. The combination of claim including a second timer circuit for energizing said timer, said second timer circuit including a third one of said timer operated switches, said third switch being closed for a predetermined interval upon the advance of said timer by the first tripping of said thermostat thereby to lock in said timer long enough to insure opening of said first timer operated switch, and said third switch being again closed upon the subsequent advance of said timer by the second tripping of said thermostat thereby to lock in said timer once more and insure the opening of said second timer operated switch.

7. Clothes drying apparatus comprising clothes 'tuinbling means, a pair of electrical heating elements, and a control system comprising a thermostat responsive to the temperature within said apparatus and opening to a tripped position at a predetermined high temperature and resetting to a normal position at a predetermined lower temperature, said thermostat having a first nor mally closed set of contacts and a second normally opened pair of contacts, a sequence control mechanism including a timer and a plurality of switches operated by said timer, a heater relay having contacts and an operating coil, a relay coil circuit including a first of said timer operated switches, said first switch being closed at the start of the drying operation to close said relay, heater circuit means including said normally closed set of the thermostat contacts and said relay contacts for energizing said heating elements, with the circuit to one of said heating elements including a second of'sa'id timer operated switches, said heater circuit means energizing both of said heating elements simultaneously until said thermostat trips a first time in response to the heat supplied by both elements, a timer circuit for energizing said timer closed by said normally open set of the thermostat contacts when said thermostat is in said tripped position, said timer being arranged to open said second timer operated switch when energized by the first tripping of said thermostat, whereby said heater circuit means energizes only the second of said heating elements upon the resetting of said thermostat to continue the drying operation, and said timer being arranged to open said first timer operated switch when said timer circuit is again energized by the second tripping of said thermostat responsive to the heat from said second heating element alone, thereby to de-energize said relay coil and open said heater circuit means.

8. Clothes drying apparatus comprising a pair of electrical heating elements, a clothes tumbling drum, a drive motor for driving said clothes tumbling drum, and a control system comprising a thermostat responive to the temperature within said apparatus and opening to a tripped position at a'predetermined high temperature and resetting to a normal position at a predetermined lower temperature, said thermostat having a first normally closed set of contacts and a second normally open set of contacts, a sequence control mechanism including a timer and a plurality of switches operated by said timer, a heater relay having contacts and an operating coil, a relay coil circuit including a first of said timer operated switches, said first switch being closed at the start of the drying operation to close said relay, a motor circuit for energizing said drive motor throughout the drying operation, said motor circuit including a second of said timer operated switches, heater circuit means including said normally closed set of thermostat contacts. and said relay contacts for energizing said heating elements, with the circuit to one of said heating elements including a third one of said timer operated switches, said heater circuit means energizing both of said heating elements simultaneously until said thermostat trips a'first time in response to the heat supplied by both elements, a timer circuit for energizing said timer closed by said normally open set of the thermostat contacts when said thermostat is in said tripped position, said timer being arranged to open said third timer operated switch when energized by the first tripping of said thermostats, whereby said heater circuit means energizes only the second of said heating elements upon the resetting of said thermostat to continue the drying operation, and said timer being arranged to open said second timer operated switch and then said first timer operated switch when said timer circuit is again energized by the second tripping of said thermostat responsive to the'heat from said second heating element alone, thereby to de-energize firstsaid relay coil and subsequently said motor circuit for de-energizing first said second heater and then said drive motor to terminate the drying operation.

9. The combination of claim 8 including a second timer circuit for energizing said'timer, said secondtimer circuit including a fourth one .of said timer operated switches, said fourth switch being closed for a predetermined interval upon the advancing of said timer by the first tripping of said thermostat, thereby to lock in said timer long enough to insure opening of said third timer operated switch, and said fourth switch being again closed upon the subequent advance of said timer by the second tripping of said thermostat, thereby to lock in said timer once more and insure the opening of said first and second timer operated switches.

References Cited in the file of this patent UNITED STATES PATENTS Gorsuch Apr. 25, 1950 Kaufiman Apr. 24, 1951 Clark Dec. 16, 1952 Robinson et a! May 10, 1955 Morrison Dec. 25, 1956

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