US2869247A - Control system for clothes dryers - Google Patents

Description

Jan. 20, 1959 FIG.|

M. F. MET

ZGER

CONTROL SYSTEM FOR CLOTHES DRYERS Filed Jan. 16, 1958 4 Sheets-Sheet 1 INVENTOR. MATT F. METZ GE R BY M My Hi5 ATTORNEY Jan. 20,- 1959 M. F. METZGER CONTROL SYSTEM FOR CLOTHES DRYERS' Filed Jan. 16, 1958- 4 Sheets-Sheet 2 FIG.3

M 7 w 5 5 W n "a 8 4 4 9 5 4 3 5 6 3 9 2 5 3 2 l 5 8 3 3 z a 4 0 5... 2 4 MI 0 3 4 Z 4 4 5...: in v n V; v 5 4 4 4 INVENTOR. MATT F'- METZGER HIS ATTORNEY Jan. 20, 1959 M. F. METZGER 2,869,247

CONTROL SYSTEM FOR CLOTHES DRYERS Filed Jan. 16, 1958 4 Sheets-Sheet 3 r r E-EE$" K :f II H 2| l8 frt'z 35 g F c G s 0 o o O ,4 1, 'J '3 G "J O O 46 22 u 0 0 0 ,-l7 3 w v A: "-30 1 0 52 O I l 23 f o o l \29 FIG, *4

INVENTOR.

MATT F. METZGIR HIS ATTORNEY Jan. 20, 1959 E R 2,869,247

CONTROL SYSTEM FOR CLOTHES DRYERS 76 FIGS F I G. 6

o FILL t 2 1 OFF WASH lamss] I RINSE 1 I conocusra HOT as com: 68 LARGE uncrzn SPIN 67 PUMP 66 wAsl-l 7| DRY 72 TIMER 64 DAMP DRY SMALL M50111:

4 8 l2. 16 2O 24 28 32 36 4O 44 INVENTOR. MATT F'- mc'rzszn H [5 ATTQRNEZY United States Patent CONTROL SYSTEM FOR CLOTHES DRYERS Matt E. Metzg'er, Jeh'ersonville, Ind}, assignor to General Electrie'Conipany, a corporation of New York Application January 16; 1958; SerialNo. 709,296

4 Claims;- (Cl. 34-45 This invention relates to control systems for automatically controlling clothes dry'ers during the drying operation, and more particularly it relates to a control system which permits Selection of a damp drying cycle as well as a regular drying cycle. The invention has general application to clothes dryers but is particularly useful in combination clothes washing and drying, machines.

In the co pending' application Serial No. 584,658 of John W. Tome; and Tohn E. Ryan, filed May 14, 1956, now Patent No. 2,819,540, and assigned to General Electric Company, owner of the present application there is described and claimed an improved control system for combination washer-dryers which in turn represents an improvement on co-pending application Serial" Number 512612 of Water Gray, Jr., filed June 2, 1955, and also assigned to General Electric Company. The washerdryers of these aforementioned applications are of the typeprovided with heating means and timing means which cooperate with each other to insure proper drying of the clothes. The aforementioned applications also each describe a' cool-down period provided subsequent to operation of the heating means. In each case the clothes are completely dried at the end of the operation, with the drying being provided to the exact proper extent by use of the combination of thermostatic and timing arrangements.

However, there are many clothes which require ironing after they have been through a drying process; many of these clothes, inturn, require pre-dampening for the ironing operation. Inotherwords, the housewife has to undo some of the effect of the dryer by once again wetting the clothes. Since it is a relatively simple matter for the housewife to segregate the clothes requiring such dampening into an individual load, it is a most desirable feature that the dryer permit the housewife to select either a full and automatic drying sequence or a sequence Where the clothes arest'ill ina damp condition at the end of the cycle so that they are ready to be ironed. It is important to provide this additional feature in a simple easily controlled manner for the convenience of the housewife, and at the same time to do so without requiring a major adjustment or a major amount of expense in the commercially produced machine described and claimed in the Toma et al. application.

The primary object of this invention is therefore the provision of a new and improved control for the drying operation of a laundry machine which provides selectively either a full automatic drying cycle or a damp dry drying cycle.

A further object of the invention is the provision of such a control, in a machine of the general type s'etforth in the aforementioned Toma et al. application, where the desired effect is obtained through the addition of a minimum of equipment and with a minimum of modification of the Toma'et al. construction.

In carrying'out' the invention in one form thereof, there is provided clothes drying apparatus having clothes tumbling means for tumbling the clothes throughout the "ice 2. length of the drying' cycle until the apparatus is shut ofi. A control system is provided which includes thermostatic means responsive to the temperature within the apparatus; the thermostatic means are movable to a normal position in response to decreases in temperature and to a tripped position in response to increases in temperature. sequence control mechanism includes a timer and switch cans operated by the timer so as to control the operations of the apparatus and of the timer itself; the switch means also operate appropriate means, such as an electric motor for instance, to actuate the tumbling means. A first energizing circuit for the timer is provided and the thermostatic means, in its normal position, opens this first circuit so as to die-energize the timer; in its tripped position, the thermostatic means complete the first circuit so as to restart the timer. The timer also controls operation of control means to control the heating means jointly with the thermostatic means so that the heating means are energized when the thermostatic means are in their normal position. After the last of a pre-determined number of trips of the thermostat the switch means deenergizes the heating means and energizes the timer independently of the thermostatic means. This provides a period of tumbling without heat until the apparatus is ultimately shut oif by the timer.

The timer operated switch will close at the appropriate time for each cycle, regardless of What final effect is desired by the housewife. Unless the manually operated switch is also closed the second timer circuit is not completed, and a full drying cycle is provided. If, however, the housewife has closed the manually operated switch, the cool-down tumbling period without heat will be started by the timer regardless of the position of the thermostatic means thereby eliminating the end of the operation of the heating means, and the housewife is provided at the end of the cycle with damp clothes all prepared for a subsequent ironing without the necessity of re-we'tting them.

The subject matter which terms this invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention however, both as to organization and method of operation together with further objects and advantages, may best be understood by reference to the following description when taken in conjunction with the accompanying drawings.

In the drawings, Fig. 1 is a front elevational View of a combination washer-dryer;

Fig. 2 is a fragmentary cross-sectional view taken along line 2-2 of Fig. 1;

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

Pig. 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 Fig. 6 is a sequence control cam chart illustrating a control system for the machine which embodies this invention in one form thereof.

Referring now to Fig. l, I have shown my invention in one form as applied to 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 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 includes a plurality of push-buttons consisting of an off button 7, hot and warm water buttons 8, a damp dry switch 9, and a dryer control or omit dry button 10. A rotatable control knob 12 is provided for convenient operator selection of any separate sequence of operations, and a second control knob 13 is included for operator selection of operating temperatures for the drying portion of the cycle of operation. 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 tube 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 and which also includes a front wall 18 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 (Fig. 4) to close this opening during operation of the machine.

During machine operation basket 14 is driven by an electric motor 23 through a drive including a pair of flexible belts 24 and 25 (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 for washing and another basket speed for centrifugal liquid extraction. The ratio of the transmission assembly is changed by any suitable means such as a spring-biased solenoid actuated plunger 31. When the solenoid 32 controlling the plunger 31 is de-energized, the transmission ratio is such that the basket is driven at a suitable speed for washing and tumbling clothes, for example, forty-four revolutions per minute. However, when 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, two hundred 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 beat 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. 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 effective heat transfer means between the heating elements and the water or other washing liquids. 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 heaters 35 and 36 it is necessary that basket 14 be rotating whenever they are energized. If either of belts.24 or 25 should fail, the basket 14 would stop rotating since it would then no longer be connected to motor 23. Therefore safety means are provided within the machine whereby the heaters 35 and 36 are deenergized 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 dc-energize the heater relay 38 (schematically shown in Fig. 5 and thereby open the heater circuit. The belt switch 37 is arranged on a pivotally mounted sled 39 which supports 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 switch 37. The arrangement of sled 39 and switch 37 is fully de scribed and claimed in Patent No. 2,750,782, issued to Daniel L. Du Hammell, Jr., on June 19, 1956, and assigned to the General Electric Company.

The means whereby water is admitted to and discharged from the tub 15 during operation of the machine is particularly shown in Fig. 3. The water supply means includes connections 40 and 41 through which hot and cold water is supplied to the machine. For the wash operation, a valve controlled by a solenoid 42 admits hot water to the machine and the valve controlled by an opposed solenoid 43 admits cold water to the machine. The hot and cold water valves under the control of solenoids 42 and 43 discharge from a common outlet conduit 44 through a suitable air gap into a funnel 45. Funnel 45 discharges into a line 46 which leads into the interior of the tub 15 through a suitable connection 47 (Fig. 4). The air gap provided by funnel 45 makes it impossible for the 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 solenoids 42 and 43 to maintain the proper water level in the machine during the washing operation. This sensing device is connected to the interior of tub 15 by a suitable line 49. 1

The illustrated machine is of the type which uses cold water during the drying cycle for condensing the moisture extracted from the wet clothes. This condenser water is admitted to the machine through an additional solenoid actuated valve controlled by a solenoid 50 (Fig. 3) which is energized during the drying operation so that the valve passes water at a slow rate sufiicient to condense the moisture extracted from the clothes. As shown, the condenser water valve discharges into line 46 through a separate funnel 51 provided as before with an air gap ahead of it to prevent supply line contamination. From the funnel the condenser water flows through line 46 and connection 47 into the tub. Condenser water flowing slowly into the tub is spread over the side of the tub by an inverted V-shaped bead 52 (Fig. 4) formed on the tub wall directly below connection 47. The condenser water being so spread out cools a substantial portion of the area of the side wall whereby there is provided a large cool surface for condensing the moisture extracted from the clothes.

The wash and rinse water used during the washing portion of the operation and the condenser water and the moisture extracted from the clothes during the drying operation are discharged from the machine through a sump 53 (Fig. 3) mounted at the bottom of the tub and connecting with a suitable discharge hose 54 which leads to a motor driven drain pump 55 to discharge to the household drain. The flow through the discharge line may, however, be controlled by any suitable means such as, for example, by a solenoid actuated drain valve.

Referring now to the schematic circuit diagram of Fig. 5 and the schematic sequenceillustration of Fig;- 6, there is shown therein a control system for the combination washer and. dryerwhichembodies the invention" in one preferred form thereof. The control system includes athermostat 56 provided withqa sensing bulb 57 within tub 1-5 tow-hich itisconnected by means of a hydraulic line 58 (see also Fig. 3). The sensing bulb 57 may, as shown, be positioned: in the gap between, the side wall of the tub andv theouter surface of the basket so as to sense a temperature of? the clothes within the basket; The temperature at the thermostat, bulb is higher than the clothing temperature but it risesand falls in a similar manner totheclothing temperature so that it can-be used as a close indication thereof.

Thermostati5-6 ha'sganormjal: position and atrip position-.- Inits normal position it closes a set of contacts 59 andopens asecondsetof: contacts 60 while in its tripped position it closes' contacts 60and' opens contacts 59. In other words, contacts 59 are' normally closed and contacts 60 are normally open. The thermostat. trips so as to open the contacts 59 and close-contacts. 60: at a piedeterminedhigh temperature: within: thetuband it resets at. a predeterminedlower temperature so as'to' open the contacts 69 and re-close contacts 59. Suitable biasing means (not shown) may be included within the thermostat. so as to allow some operator selection of the trip and resetting temperatures. The thermostat 56 is used in: this. control system for the .prime purposeof control-' lingheaters and 36' duringzthe drying operation and for controlling the actual length of the operationitself.

A sequence control arrangement is provided which is utilized in conjunction with the thermostatduring the drying operation. and independently during the washing operation; The basic operation of the sequence control arrangement is provided by means of a suitable timer motor 61 and it includes a series of switches 62 through 72 which are actuated in adesired sequence by appropriate switch operating means driven bythe timer, as indicated schematically by-Fig. 5 Seque'nce controls are'well known, and several types are commercially available; the representation of Figs; 5 and 6 is therefore purely schematidit being understoodthat each of theswit'c'hes 62 to 72 is operated bymea'ns such as ca'rns'. In-th'e particularrepreseatatibn or Figs 5' and 6 it is to be understood that each of the switches 6272 schematically shown in Fig; 5 is closed during the periods indicated by th'e'heavy black lines in Fig. 6.

For example; switch 70 is actuated toits closed position on thediagrarn from point 28- to point; A scale has been shown on the cam ch'arfi'of Fig: 6; but it wil1 be understood that the scale is not necessarily timed but shows the length of the impulses given by advancing the cams'in the forward rotational direction. In" other words;

the chart of Fig; 6 may be re arded for" the purpo'ses of this" application to be a development of the peripheries of the respective switch operating earns, theheavy lines' showing the cam rises. Further, it will be understood that the timer camsare preferably driven with an impulseor intermittent motion by means'of a. suitable mechanism (notshown) connected between them and the timer motor.- Thus, at switchover points where the chart shows one switch opening and another closing there is a quick make and break action so that'one switch is closed simultaneously as the other is opened.

Further details with respect to the operation of the new and improved control system will become apparent by a review of a typical sequence of" operation. Since the invention is" particularly directed to a' phase of the control of the drying operation, the drying operation will be explained first. It will be understood, however, that normally the drying operation will be preceded by, and will renew automatically, the washing operation. Referring to Fig'. 6, it will be seen that the drying operati'on begins at point 28 of'the scale and that at thatpoint the switches 62, 64, 65, 66, 70' and 72 of the sequence control are closed. The remaining switches of the control are open. Energization of motor 23' without energization of solenoid 32 provides the tumbling speed-circuit. With this switch arrangement, both heating elements 35 and 36,- drive motor 23, condenser water valve solenoid 50, the drain pump 55, and the timer motor 62 are all energized. The power for energizing these elements is supplied from a three-wire power source comprising power supply lines and 76 and a neutral line 77. This three-wire source may, for example, comprise the conventional 230 volt domestic supply having a voltage of 230 volts between supply lines 75 and 76 and a voltage of 115 volts between each of the supply lines and neutral line 77.

It is to be understood that a complete description of every element required in a circuit for connecting the various electrical components across the supply line and the neutral line is omitted for the sake of clarity; in fact, such a complete circuit is readily apparent to one skilled in the art, and one, for instance, is shown and described in the aforementioned Toma et al. application. However, for the sake of not providing unduly lengthy explanations irrelevant to this invention, it is believed that the general construction will be amply clear from the schematic illustration of the connections as shown in Fig. 5.

Returning now to the description of the circuit, the drive motor 23 is energized across supply conductor 76 and neutral line 77 through switch 72 to provide tumbling speed rotation of the basket. Included in this circuit is omit dry switch 10 which is manually opened when it is desired that the operation of the machine cease at the end of the washing cycle (to be described) and which is closed as shown when a drying cycle is desired. In addition to energization of the motor, both heaters 35 and 36 are energized at the beginning of the drying: cycle so as to apply maximum heat tothe clothes as they are tumbled. In order to energize the heaters, heater relay 38 is energized by a circuit between conductor 76 and neutral line 77 through switches 72, 10 and 65. Energization of relay 33 closes switch arms 79 and 80 on contacts 81 and 82 respectively. This action connects both heaters 35 and 36 across lines 75 and 76 so that the heaters are energized across a 230 volt potential. In the case of heater 35, this is eifected from line 75 through switch blade 79, contact 81,.heater 35, contacts 59 bridged by the thermostat 56, contact 82, and switch blade 80 toline 76. In the case of heater 36, the circuit is essentially the same with the single exception that heater 36 is connected in parallel with heater 35 through the medium of closed timer operated switch 62. Thus, both heaters are energized together until such time as thermostat 56 trips and opens the contacts 59. At that time both heating elements are de-energized simultaneously.

During heating, the moisture extracted from the clothes by the heating elements 35 and 36 is being condensed by the water provided through the energization of condenser water solenoid 50 as a result of the closing of switch 70 by the timer to complete the connection between lines 76 and 77 of the condenser solenoid. The condenser water which enters 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. Switch 66 is closed to energize the drain pump 55 across line 76 and neutral conductor 77 so as to discharge condenser water and condensed moisture from the machine.

At the start of the drying operation, timer motor 61 has also been energized between line 76 and the conductor 77 through the closure of switch 64; the timer motor thus.

continues to run until switch 64 opens. It will be observed by referring to Fig. 6 that switch 64 remains closed only for a brief period after the washer-dryer proceeds into; the drying cycle. Specifically, it remains closed so as to. energize the timer motor long enough for the timer motor- I to 'close'all the other switches necessary'for the drying cycle as set forth above. Thereafter switch 64 is opened which causes the timer motor to be de-energized and this in turn places the control of the heating elements and of the machine itself under the action of thermostat 56.

During the initial period it is generally desirable to have heating elements 35 and 36 both energized as described so as to supply maximum wattage for heating the clothes. A satisfactory design has been found, for instance, to provide a total of 4,000 watts, with heater 35 being approximately 2800 watts and the other heater 36 being approximately 1200 watts.

Both heaters remain energized, applying maximum heat to the clothes, until the machine heats up far enough to cause thermostat 56 to trip at which point, as is fully explained in the Toma et al. application, substantially all of the surface moisture has been removed from the clothes, with, however, an appreciable amount of moisture still remaining in the fibres of the clothes. It has been found that in the illustrated machine a desirable trip temperature for the thermostat is 230 with a normal load of clothes being dried, the trip point being slightly higher if there is more moisture to be extracted from the fibre such as for heavy fabrics like shag rugs and dungarees, and being lower for a load of delicate synthetic fabrics. When the thermostat 56 trips, contacts 59 are opened and contacts 60 are closed. The opening of contacts 59 breaks the heater circuit so that both heaters 35 and 36 are de-energized and the machine immediately starts to cool down. However, the closing of contacts 60 energizes timer motor 61 once more between supply line 76 and neutral conductor 77 through switch blade 80 and contact 82. This is effected by the connection through conductors 83 and 84 which connect one side of the timer motor to one of the contacts 60. The timer motor, energized through this circuit, begins to drive the sequence control mechanism. Shortly after it starts to operate, that is, about at point 33 on the scale of Fig. 6, the timer causes switch 64 of the sequence mechanism to close which locks the timer in and continues it in operation even if the thermostat should reset immediately thereafter. Also, after the timer starts to operate, it opens switch 62 thereby breaking the circuit to the heating element 36 so that it cannot be re-energized even when the heater circuit is reestablished through the thermostat. The timer now also closes switch 63. After this, the sequence control mechanism then continues to operate for a brief period of time while the thermostat cools, and then switch 64 is once again opened to make completion of the timer circuit entirely dependent on the closed position of thermostat contacts 60. The machine continues to cool down due to the de-energization of the heating element. At a predetermined temperature below the trip temperature the machine cools down enough for the thermostat 56 to reset and return to its normal position reclosing contacts 59 and opening contacts 60 thereby completing the heater circuit once again and de-energizing the timer motor. However, with switch 62 opened by the timer only heating element 35 is energized and not heating element 36. Thus, only 2800 watts rather than 4000 are now applied to the clothes for the evaporation of the remaining moisture contained within the fibres.

If switch 9 is in its open position, that is, a damp dry operation is not desired, the closing of switch 63 by the timer has no effect upon the operation sinceswitch 9 is directly in series with switch 63. In this case, the drying action now continues on heater 35 alone until the trip point of thermostat 56 is reached once again. At this point (39 on the chart), the clothes are substantially dry, this is, an amount of moisture equal to approximately of the dry weight of the clothes remains in them so they are completely dry to the touch. .However, even if this 5% of moisture should evaporate no damage can be done since disappearance of all moisture will cause the machine to heat up very rapidly to the trip point and heater 35 will then be de-energized by the opening of contacts 59 before any substantial overheating can occur..

The tripping of thermostat 56 for the second time again opens contacts 59 and closes contacts 60, thus de-energizing the heating element 35; as before, this re-energizes. the timer motor 61. The timer motor now drives thetimer mechanism toward the off position of the washer-- dryer. Also, shortly after the timer motor again goes intooperation, the sequence control switch 64 is closed so as to lock in the timer circuit, and switch 65 is opened to open the circuit to the heater relay 38 so that switch arms 79 and 80 move out of contact with contacts 81 and 82 respectively. Thus, resetting of the thermostat cannot close the heater circuits.

The machine continues in operation with the heaters off and with the timer motor running for a predetermined period (point 39 to point 44) which provides a cooldown period for the clothes to come down to a suitable temperature at the point marked off on the chart. The timer mechanism then opens switch 72 which de-energizes all of the elements of the control including the timer motor, the drive motor, the drain pump, and the condenser water solenoid, thereby terminating the operation of the machine.

The foregoing, with the exception of the description of switches 9 and 63, represents in essence a summary of the operation of the control described and claimed in the above mentioned Toma et al. patent application. The present application proposes, for that type of circuit, to add simply and economically, a damp dry sequence as well as the complete drying sequence just described; this is effected by the addition of switches 9 and 63 in series as described. One end of the added circuit is connected to the line 84, between switch 64 and line 83, while at its other end the new circuit is connected to point 86. When it is desired to provide the damp drying circuit, switch 9 is closed so that contacts 87 in Fig. 5 are closed. When this is done, the operation in the drying cycle is substantially the same as described through the first heating operation requiring both heaters 35 and 36. However, with switch 9 closed, the closing of switch 63 insures completion of a circuit through timer motor 61 even after the timer motor opens switch 64 at point 37 on the cam chart and the thermostat thereafter trips back to its normal position. At this point, in an ordinary drying cycle, the timer would stop operating.

In the normal drying sequence, the movement of thermostat 56 to bridge contacts 59 and open contacts 60 stops the operation of the timer motor 61. However, to the contrary, with switches 9 and 63 closed a circuit is still completed to the timer motor as follows: line 76, switch arm 80, contacts 82, contacts 59, line 88, switch 63, switch 9, conductor 83, timer, motor 61 and conductor 77. With the timer motor continuing to run, only a relatively brief period of heating, if any, is provided from heater 35 before the timer opens switch 65 to de-energize relay 38 thereby opening switch arms 79 and 80 and deenergizing the heater. Thus, the continued operation of timer motor 61 as a result of the use of switches 9 and 63 provides a time limit on the amount of time of operation of heater 35 by itself and stops the energization of heater 35 without regard to the last tripping of the thermostat 56, substantially prior to the point at which the thermostat would normally operate. In this manner, sufficient dampness is maintained in the clothes so that they are ready for ironing and may be removed from the machine and ironed immediately without any interme, diate step of dampening being necessary.

To complete the description of the control system of Fig. 5, the operation of the machine during the washing operation will now be briefly explained. For this purpose, let it be assumed that the sequence control is set in the space just preceding 0 on the scale of the cam chart, that is, in the off position. To initiate the washing operation the sequence control is now manually advanced to a position slightly beyond 0. As a result, cam actuated switches 62, 66, 69 and 7 1 are closed, with the other switches being open. The closure of-switch 71 provides an energizing circuit for the main drive motor 23 across line 76 through switch 71, switch 67, contact 73, motor 23 and conductor 77. Also, an automatic water fill control is simultaneously energized through cam actuated switch 69. This causes hot water to be provided through conduit 46 into tub until such time as pressure sensitive switch 48 opens the circuit to de-energize solenoid 43. It will be noted, that if so desired, a manually operated switch 8 may be actuated to cause the cold water solenoid to be energized at the same time as the hot water solenoid to provide warm water .until actuation of pressure sensitive switch 48.

The tumbling washing action continues through the proper period, as determined by the timer motor 61 through its associated switches, and thereafter at point 11 on the cam chart scale the wash period terminates and wash water is discharged from the machine by the drain pump 55. This is achieved under the control of switch 66 which closes to energize the pump between lines .76 and 77. At the end of the drain period, switch 68 closes to initiate the fill operation in the manner previously described in connection with the wash fill. Operation of the solenoid is again dependent on pressure sensitive switch 48 so that the supply of water is cut ofi after the appropriate amount has been introduced into the tub. The first rinse then takes place, and the rinse water is then drained from the machine by reclosing of switch 66 to re-energize the drain pump 55. At the end of this second drain the appropriate supply solenoids are again energized, and for the particular sequence illustrated, a warm rinse fill is provided by energization of both the hot and cold solenoids The water then again enters the tub until actuation of the pressure responsive switch 48 and the last rinse then takes place. At the end of this rinse the pump 55 is again energized through the closing of switch 66, After the free water has drained out through the pump as before, a spin or extraction cycle is provided through timer motor 61 closing switch 67 to energize solenoid 32 and provide a spin action as previously briefly described. At the end of the desired spin. action, switch 67 opens and the motor provides once again tumbling speed for the basket. At this time switch 71 is opened by the timer and, if switch 10 is also open, the entire operation ceases, with the clothes in a damp condition as a resultof the. washing, rinsing, and extraction actions.

If, however, switch 10 is closed, then the closing of switch 72, which occurs slightly before the opening of switch 71, will serve the same purpose as switch 71 serves and will continue to provide an electric path for the completion of the circuits through the various operating components. At this point then there starts the drying sequence which has previously been described in substantial detail.

It will be seen from the foregoing that the invention provides, in a combination washer-dryer machine, an improved control for the dryer portion of the sequence whereby a damp dry may also be readily provided as well as a complete automatic drying operation. It will further be clear that while for clarity the washer portion of the cycle has been briefly and schematically described the invention resides in the modification to the drying sequence and is thus equally applicable to separate clothes drying apparatus as well as to combination washer-dryers.

While in accordance with the patent statutes I have described what at present is considered to be the preferred embodiment of the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the invention and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

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

1. Clothes drying apparatus for tumbling clothes throughout a drying cycle comprising clothes tumbling means; electrical heating means; a controlsystem comprising thermostatic means responsive to the temperature within said apparatus, said thermostatic means being movable to a normal position in response to decreases in temperature and to a tripped position in response to increases in temperature; a sequence control mechanism including a timer and switch means operated by said timer for controlling the operations of said apparatus and said timer;

means operable by said switch means for operating said tumbling means; a first energizing circuit for said timer; said thermostatic means in said normal position opening said first circuit to de-energize said timer and in said tripped position completing said first circuit to re-start said timer; control means operated by said timer for controlling said heating means jointly with said thermostatic means to effect the energization of said heating means when said thermostatic means are in said normal position; said switch means operating to effect the de-energization of said heating means upon the last of a pre-determined number of trips of said thermostatic means and energizing said timer independently of the operation of said thermostatic means thereby to provide a period of tumbling without heat and ultimately shutting off said apparatus; and a second energizing circuit for said timer including one of said timer operated switches and a manually operated switch in series relation and each having a closed position and an open position; said thermostatic means, when in said normal position, enabling closing of said second circuit; said timer being arranged to close said second circuit timer operated switch during its operation in response to the next to last of said pre-determined number of trips of said thermostatic means whereby said timer, when said manually operated switch is closed, continues operation without regard to starting of the last heating operation and therefore starts the unheated tumbling period prior to said last thermostatic means trip.

2. Clothes drying apparatus for tumbling clothes throughout a drying cycle comprising clothes tumbling means; electrical heating means; a control system comprising a thermostat responsive to the temperature within said apparatus, said thermostat being movable to a normal position in response to a decrease to a predetermined low temperature and to a tripped position in response to an increase to a predetermined high temperature; a sequence control mechanism including a timer and switch means operated by said timer for controlling the operation of said apparatus and said timer; electric motor means operable through said switch means for operating said tumbling means; a first energizing circuit for said timer; said thermostat in said normal position opening said first circuit to deenergize said timer and in said tripped position completing said first circuit to re-start said timer; control means operated by said timer for controlling said heating means jointly with said thermostat to effect the energization of said heating means when said thermostat is in said normal position; said switch means operating to effect the de-energization of said heating means upon the last of a predetermined number of trips and energizing said timer independently of the operation of said thermostat thereby to provide a period of tumbling Without heat and ultimately shutting off said apparatus; and a second energizing circuit for said timer including one of said timer operated switches and a manually operated switch in series relation and each having a closed position and an opened position; said thermostat, when in said normal position, enabling closing of said second circuit; said timer being arranged to close said second circuit timer operated switch during its operation in response to the next to last of said predetermined number of trips of said thermostat whereby said timer, when said manually operated switch is closed, continues operation without regard to starting of the last heating operation and therefore starts the unheated tumbling period prior to said last thermostat trip.

ture; a sequence control mechanism including a timer and a plurality of switches operated by said timer for controlling the operations of said apparatus and said timer; motor means operable through one of said switches for operating said tumbling means; a first energizing circuit for said timer; said thermostat in said normal position opening said first circuit to de-energize said timer and in said tripped position completing said first circuit to restart said timer; control means operated by said timer for controlling said heating units jointly with said thermostat to enable the energization of said heating units when said thermostat is in said normal position; a second of said switches being in series with one of said heating units, said timer opening said second switch during its operation in response to the first trip of said thermostat; a third of said switches operating to effect the de-energization of both said heating units upon operation of the timer in response to the second trip of said thermostat and a fourth of said switches operating to energize said timer independently of the operation of said thermostat thereby to provide a period of tumbling without heat, said timer then ultimately shutting off said apparatus; and a second energizing circuit for said timer including a fifth of said timer operated switches and a manually operated switch in series relation and each having a closed position and an opened position; said thermostat, when in said normal position, enabling closing of said second circuit; said timer being arranged to close said fifth switch during its operation in response to the first trip of said thermostat whereby said timer, when said manually operated switch is closed, continues operation without regard to starting of the last heating operation on said one heating unit and therefore starts the unheated tumbling period without waiting for said last thermostat trip.

4. Clothes drying apparatus for tumbling clothes throughout a drying cycle comprising tumbling means; a pair of electrical heating elements; a control system comprising a thermostat responsive to the temperature within said apparatus, said thermostat being movable to a normal position in response to a decrease to a predetermined low temperature and to a tripped position in response 12 to an increase to a predetermined high temperature, said thermostat having a first normally closed contact and a second normally open contact which is closed when said thermostat trips; a sequence control mechanism including a timer and a plurality of switches operated by said timer for controlling the operations of said apparatus and said timer; motor means operable through one of said switches for operating said tumbling means; a first energizing circuit for said timer; said thermostat in said normal position opening said first circuit to de-energize said timer and in said tripped position completing said first circuit through said normally open contact to restart said timer; a heater relay for controlling energization of said heating elements having contacts and an operating coil; a relay coil circuit including a second of said switches whereby said timer controls said heating elements jointly with said thermostat to effect the energization of said heating elements when said thermostat is in said normal position; the circuit to one of said heating elements including a third of said timer operated switches; said timer opening said third switch to de-energize said one heating element in response to operation of said timer after the first trip of said thermostat; said timer operating said second switch to de-energize said heater relay during its operation after the second trip of said thermostat; a fourth of said switches completing a second circuit to energize said timer independently of the operation of said thermostat thereby to provide a period of tumbling without heat, said timer then ultimately shutting off said apparatus; and a third energizing circuit for said timer including a fifth of said timer operated switches References Cited in the file of this patent UNITED STATES PATENTS 2,654,961 Manecke Oct. 13, 1953 2,717,455 Harris et al Sept. 13, 1955 2,819,540 Toma et a1. Jan. 14, 1958

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