US2875526A - Combined washer and drier - Google Patents

Description

March 3, 1959 J A. ENGEL ET AL 2,875,526

COMBINED WASHER AND DRIER Filed Dec. 1, 1955 v 2 Sheets-Sheet 1 INVENTORS. J. ANTHUNY EMGEL By E: m-mnn [LLAMKm ATTORNEY COMBINED WASHER AND DRIER J Anthony Engel, Syracuse, and Richard 'C Lamkin,

Skaneateles, N. Y., assignors to The Murray Corporation of America, Syracuse, N. Y., a corporation of Delaware Application December 1, 1955, Serial No. 550,353

2 Claims. (Cl. 34-45) This invention relates to laundry washer and drier combinations in which laundry is first washed and subsequently dried without intermediate handling, and particularly relates to such a machine in which a substantially horizontal tumbling drum is employed which oper-,

ates as a centrifugal extractor and drying tumbler and in which the drying timer automatically varies with the load.

In combination washing and drying machines of the type referred to, a time control fixing a period for drying has been proposed. 1 When the load is light, the overload thermostat prevents undue temperature rise, but the drying time remains fixed, for a period sufficient to dry a heavy load. For fabrics which cannot stand too much prolonged heat, such apparatus requires a low heat thermostat which usually is manually selected.

The present invention is directed to an improvement in the time control of the drying cycle wherein when drying heat is applied, the timer is stopped. When the heat exceeds a safe maximum, the heat is cut oil? and the timer starts, until the heat is again cut on. The cycle of heat on, and heat oif, continues until the increments of time during which the timer actually operates exceed a predetermined time, whereupon-the tumbling action and blower continue for a fixed runout time without heat to complete the drying cycle.

The arrangement is such that with a heavy load, the time for the temperature to reach the safe limit is increased. When the heat is cut 01f, the evaporation of a heavy load is such as to quickly cool the apparatus to bring the heat on. Thus the timer operation period is reduced in length, allowing at least as many heat on and off cycles for a heavy load, and at the same time providing for longer heat on periods. With a light load, the safe temperature is quickly reached, and such temperature gradually reduces more from cooling air currents than evaporation, so the timer operates over a longerincrement of time before the heat is again turned on, resulting in fewer heat on and off cycles, and shorter heat on increments, so that drying is completed expeditiously. Since the total time varies with the load, a lower maximum temperature may be employed which is safe for all fabrics, and while the drying time for a heavy load may be somewhat extended, yet a light load will be handled in a much shorter time. A fixed period for all loads is thus eliminated, and the necessity for a housewife to select a proper period is automatically taken care of.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims. 1

In the drawings, wherein like reference characters, indicate like parts:

Figure 1 is a diagrammatic view of a washing and dryingapparatus in which the inventionmay be performed;

tates Patent 2,875,526 Patented Mar. 3, 1959 ICC Figure 2 is an electrical circuit diagram for operating the mechanism of Figure 1;

Figure 3 is a time chart indicating the operations of the cams of thetimer controlled switches shown in Figure 2;

Figure 4 is a time temperature digram showing the heat on, and timer on and heat otf periods for a heavy load; and,

Figure 5 is a similar time temperature diagram for a light load.

The invention has been applied to an apparatus similar to that shown in copending application 501,661 filed April 15, 1955, the apparatus being modified as will appear.

Referring to Figure 1, there is shown a tub 10 arranged on a substantially horizontal axis in which there is journalled a wash drum 12, the drum being journalled in a back Wallbearing 14 of the tube 10. The drum 12 may be loaded through an access door 16 as indicated, and the drum 12 is driven by a motor 18 having a. two-speed transmission 20 located in the end bell thereof or otherwise as desired. The transmission is adapted to drive the drum at a tumbling speed such as to 60 R. P. M. during wash and final drying, and at a higher speed as for example, 500 R. P. M. during centrifugal extraction. The transmission is shifted from the low speed to the high speed by the energization of the solenoid 22 of an l6ClIO-.

magnetic clutch associated with the transmission.

The wash drum and tub may if desired, correspond to that shown in Eagle application Serial No. 496,148 filed March 23, 1955, wherein the drum 12 is provided with overflow holes such as 24 to establish a maximum wash water level indicated as at 28 within the drum. The drum is also provided with scoops 26 all facing in the same direction and adapted to continually during rotation lift water from the outer tub and deliver such water through communicating passages 27 into the drum to maintain the water level 28. The outer wall of the drum 12 may be tapered slightly outward toward the scoops at the rear to facilitate water removal during centrifugal extraction.

In such an arrangement, the outer tub is supplied with wash water of a proper temperature by a pressure regulating valve 30, which will establish an approximate level within the tub as indicated at 32. The overall supply of such Water is controlled by a solenoid valve 34. Drainage of the tub is controlled by a solenoid-operated valve 36. The tub is also provided with an air blower 33 for withdrawing air from the tub through a duct 39 leading to the door 16 and screen 42. There is also provided an electric heater 40 which is adapted to heat air entering the tub 10 after which it flows from the tub 10 through the scoop openings 27 into the drum 12. .Air is exhausted from the tub 12 through any suitable means such as the screen 42 in the door 16 and the duct 39 as described. The blower 38 is only operated during the drying portion of the cycle and is driven by a motor 41 having a centrifugal switch 44. Air is admitted to tub 10, above the water level, as at 37.

In Figure Zthere is shown a circuit in which there is provided a timer motor 46 for driving a cam shaft48 which actuates cam switches 50, 52, 54, 56, 58, 61 and 63. The timer and cam assembly may be of the type shown in Patents 2,227,133 and 2,313,064 issued December 31, 1940 and March 9, 1943 respectively. Such timer advances the cams in stepwi'se fashion at fixed intervals switch of the blower motor, and one branch 65 of a sole-.

noid actuated single pole double throw switch 67, which branch is normally open unless the solenoid 55 is energized.

In the chart shown in Figure 3, the intervals indicated crosswise of the chart are 25 second intervals; The bars indicate the various lengths of time that the cam switches 50 to 58, 61 and as inclusive are closed during a complete cycle of operation. The cam shaft is initially manually rotated to start operation, and by advancing the cam shaft so as to bring the cam switches to the position indicated at 76, it will be seen from the chart that the timer motor switch 56 is closed to energize the circuit to the timer motor 46, so that the cam shaft is subsequently driven and periodically advanced by the timer motor. At the same time, the motor switch contacts 52 are closed and the water inlet valve 34 is opened and the drain valve 36 is closed by the contacts 5t Initially during the wash period, water is delivered to the drum 12, and the lever 28 is maintained. After a short wash period which may terminate following the passage of 5 intervals, for example, as is indicated at '72, the drain valve is opened and the water inlet valve 34 closed and the spin-solenoid 22 is actuated to high speed position for a brief interval of 25 seconds as indicated at 56. The drum is gradually accelerated While the water drains out of the tub and drum 12, and a certain amount of the wash water entrained in the laundry is centrifugally extracted from the laundry in the drum 12.

After a second period of 25 seconds during which the drum is allowed to reduce its speed to the tumbling speed, the drain valve is again closed and the water inlet valve opened, whereupon a rinsing operation takes place, which may continue for a period of 6 intervals as indicated by the bar 75, terminating at 76, at which time the water supply valve 34' is closed and the drain valve 36 opened.

Continued rotation of the drum takes place for one 25 second interval while draining to reduce the laundry to a saturated state, and thereafter at 7 8 the spin-solenoid is energized and the drum caused to accelerate for a single interval of 25 seconds as represented by the bar 79, after which the motor contacts 52 are opened and the spin-solenoid contacts 54 are also opened. Following a 25 second period during which the drum comes to.

rest, and the partially extracted but still relatively heavy laundry is allowed to drop from the wall of the drum,

the motor contacts 52 are again closed as at 31 and following a 25 second interval of tumbling, the spinsolenoid contacts 54 are closed, the drum accelerated, and completion of the centrifugal extraction takes place over an interval as indicated at 83 of approximately 3 periods. Thereafter, the motor contacts 52 and the spin-. solenoid contacts 54 are opened and the drum stops rotating. As soon as the drum stops rotating, the laundry drops from the wall thereof, and subsequently the motor contacts 52 and the heat control contacts 58 are closed.

The heat control contacts 58 are in circuit with a safe limit thermostat 66, and a safety high limit thermostat 69, and the solenoid 55 of the switch 67. At the same time the blower contacts 63 are closed, and if the door switch 17 is closed in response to door closure, the blower motor 41 starts, closing centrifugal switch contacts 44. The centrifugal switch contacts act as a safety precaution, since if the blower is not running, the heat will be cutoff.

When the heat control timer contacts 53 close, the solenoid 55 of switch 67 is energized closing contacts 65 and opening contacts '71, which latter contacts are in series with the timer motor ss. Thus the timer motor stops. As the temperature rises from the heating effect of heater 4d, and reaches the safe limit of thermostat 66, the thermostat opens the circuit, and the solenoid switch closes contacts 71, and opens contacts: 65, starting the timer during a cooling period; When the lower'lirnit. of the thermostat 66 is reached, the circuitis again closed, the solenoid 55 again energized, the

timer stopped and the heater energized. The cyclic operation repeats, until the sum total of the increments of timer operation during the cooling periods equals a predetermined period of timer operation as determined by the length of the cam 87, at which time, contacts 58 open, and the timer continues to operate through the remainder of the period represented by the length of the cam 88, operating switch contacts ss.

During such period the blower motor 41, operated by cam switch 63, and the tumbler motor 20 operated by cam switch 52 continue to run for like periods, which terminate prior to the opening of the timer cam control contacts 56. As shown in Figure 3, the cam 88 which actuate contacts 56 extends one timer advance period beyond earns and 98 which actuate the motor and blower contacts 52 and 63 respectively.

In the diagram of Figure 3, the lines 100, 101, 102, 103 and 104 indicate five arbitrary timer positions, when the timer motor is stopped, and the heating currents are on. The time interval between such lines indicates the increments of time during which the timer motor is running. In Figure 4 the rising temperature curves 105, represent the period of time the timer motor is at rest. When the maximum temperature of thermostat 66 is reached, the circuit to the solenoid 55 is broken, and the circuit to the heater is broken, and the timer motor recommences to advance the timer while the temperature drops as represented by the declining curves 107. When the thermostat lower limit is reached, the solenoid 55 is reenergized, heat cut on, and the timer again stopped. The total time period consumed by the declining temperature curves finally totals the time period represented by the cam 8'7, and the contacts 58 are then opened, deenergizing solenoid 55 for the balance of the drying period. Cams 98 and 85 continue the tumbling and blower operation for a fixed period, after which the drum and blower are stopped, and the timer motor then cuts itself oif.

If a light load is placed within the drum, the cycle of heat on and heat off periods would be represented by a diagram such as that shown in Figure 5. The temperature rises, indicated at 109, are more rapid, and the temperature drops 111, during which the timer motor is running may be longer than before because of less evaporation from a smaller load. It can be seen, in any event, that the drying time issubstantially reduced, since the total increments of time during temperature rise are substantially reduced, whereas the increments of time during temperature drops, during which the timer motor is operating, whether increased or decreased inlength will advance the timer after a plurality of short heat on and off cycles to the position resulting in the opening of switch contacts 58.

1 From the foregoing it will be apparent that the actual drying time will automatically vary with the load, and that by operating within a safe temperature range, as, determined by thermostat 66, a light load will notbe subjected to prolonged tumbling and heat, long after the load has become dried.

The operation thus provides for an automatically variable drying period repsonsive to load size, followed by a fixed terminal period of short duration, during which final tracesof moisture and cooling takes place.

Dryer operation depends on the tumbling of the load whilecirculating a drying medium therethrough. It is essential that after the centrifugal extraction period, that the laundry not adhere to the internal drum surface. It will be seen thatginthe brief 25 second spininterval following the rinsing portion of the cycle, that the laundry centrifugally. thrown against the drum wall will have had insufficient time to lose more than about one-half of the loose, or-centrifugally extractable water entrained. therein. This results in a considerable amount of the moisture beingremoved during this interval, but at the same. time leaving a substantial amount in the laundry so as to give it a considerable weight. Thus, when the drum stops rotating, the weight of the laundry with the remaining moisture is sufficient to cause the laundry to drop away from the drum wall and be subjected to further redistribution during the subsequent 25 second tumbling interval prior to the final extraction period. When final extraction commences, the laundry having had a part of the moisture removed therefrom, does not have the weight nor the wet limpness which it originally had, and consequently when it is centrifugally held against the internal wall of the drum, it is not held against said wall with the initial centrifugal force present when the laundry was soaking wet. The laundry is not so wet and flexible as to readily form itself about irregularities and projections on the initial drum wall which might otherwise result in adhesion. Thus the adhesion between the laundry and the internal tub wall which is created during the final centrifugal extraction, is insufiicient to cause the laundry to stick to the drum when the centrifugal extraction is completed and the drum stops rotation.

If a perforate drum is employed, the initial extraction will be more rapid because of the direct radial flow of water from the laundry through the drum perforations. In such a case, the interval of the initial centrifugal extraction should be reduced to approximately seconds.

The timer may be provided with ten second intervals in such a case, or a relay circuit, which will be effective to stop the spinning at the end of 10 seconds, may be employed. Where the shorter timer intervals are used, the wash period and other periods will employ a greater number of such intervals to provide the proper lengths of time.

The timer may operate on 25 second or other longer intervals, and to obtain a 10 second spin interval, as in a perforate drum, where 25 second intervals are provided for, the spin solenoid circuit including contacts 54, may have an additional pair of contacts 57 opened after 10 seconds by a time delay solenoid 59, in circuit with an additional set of contacts 61 operated by a sixth cam. Such contacts 61 will only be closed during the same single interval period that contacts 55 are closed following the rinse, as is indicated in Figure 3. The relay will be set to open the contacts 57 at the expiration of 10 seconds. The contacts can be allowed to reclose, before the final spin is efiected, or after the expiration of the 25 second period indicated at 61 in Figure 3.

Though a single form of the invention has been illustrated or described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A laundry appliance comprising a tumbling drum adapted to receive laundry, a motor for driving the drum, means for heating the contents of the drum to effect dry ing of the laundry contained therein, said means being adapted to supply heat in excess of demand, a thermostatic control for the heating means responsive to temperature within the drum, a timer control having a timer driving motor and a plurality of cam actuated switches, a solenoid switch adapted to'alternately establish a circuit including said timer motor and one of said cam actuated switches and a heater circuit for energizing said heating means, a circuit including another of said cam operated switches said thermostat and solenoid and said cam operated switch in circuit with said timer motor, another circuit including one of said cam operated switches and said driving motor, said cam operating switch for operating the solenoid and controlling the timer motor being operative to drive the timing motor during deenergization of said heating means and adapted to establish an overall period of successive deenergization time increments, and said cam operating switches for said driving motor and said timer motor being adapted to establish an overall period of timer motor operation of greater duration than said overall period.

2. In a dryer control, a pair of line connections and a neutral connection, a timer having a timer motor and a plurality of timer actuated cam switches connected to said neutral connection and an additional cam switch, a tumbling motor and tumbling drum driven thereby, a thermostatically controlled solenoid actuated double throw switch sensitive to tumbling drum temperature, a blower motor and a heater resistance for circulating heated air through the drum, said heater resistance having excess heating capacity and being connected to one of said line connections and through one side of said. double throw switch to the other line connection, said timer motor being connected to the other side of said double throw switch and to one of said neutral cam switches, said blower motor being connected between another neutral cam switch and said other line, said tumbling motor being connected to one of said neutral cam switches and a line connection, and said thermostatically controlled solenoid being connected to said other line connection and through said additional cam switch and to the timer connection to the timer cam switch, the cam switch for said blower circuit being adapted to open intermediate the sequential opening of said thermostatic cam switch and said timer motor cam switch.

References Cited in the file of this patent UNITED STATES PATENTS 2,454,392 Jorgenson Nov. 23, 1948 2,505,041 Gorsuch Apr. 25, 1950 2,590,808 Wagner Mar. 25, 1952 2,652,708 Rimsha et al. Sept. 22, 1953 2,743,532 Steward May 1, 1956

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