US2624352A

US2624352A - Control circuits for dishwashing apparatus

Info

Publication number: US2624352A
Application number: US91906A
Authority: US
Inventors: Douglas F Illian
Original assignee: HOTPOINT Inc
Current assignee: HOTPOINT Inc
Priority date: 1949-05-07
Filing date: 1949-05-07
Publication date: 1953-01-06
Anticipated expiration: 1970-01-06

Description

Jan. 6, 1953 D. F. ILLIAN CONTROL. cmcurrs FOR DISHWASHING APPARATUS 2 SHEETS-SHEET 1 FIG. 2 \0 Filed May 7. 1949 FIG. 1

FIG. 3

INVEN TOR.

Douglas E Itliun ATTYS.

Patented Jan. 6, 1953 CONTROL CIRCUITS FOR DISHWASHING APPARATUS Douglas F. Illian, Oak Park, Ill., assignor to Hotpoint Inc., a corporation of New York Application May '7, 1949, Serial No. 91.906

Claims. 1

The present invention relates to cyclic control program systems and more particularly to improved control circuits for dishwashing apparatus of the general character of that disclosed in the copending application of Edgar S. Stoddard, Serial No. 86,291, filed April 8, 1949.

The dishwashing apparatus disclosed in the Stoddard application mentioned is of the timed washing cycle type that performs automatically and in predetermined sequence given steps including spraying, washing, rinsing and drying of the dishes and other utensils contained therein. This apparatus comprises a cabinet housing a. vertically disposed vat including a front opening and a door for closing the front opening, the door being mounted for movements between a substantially vertical closed position and a substantially horizontal open position. Also this apparatus comprises rack structure for supporting the dishes and other utensils that is movable over the door in its open position into and out of the vat through the front opening.

It is a general object of the present invention to provide in dishwashing apparatus of the character described an improved control circuit of simple connection and arrangement for the purpose of effecting efficient and positive operation of the dishwashing apparatus through its washing cycle.

Another object of the invention is to provide in dishwashing apparatus of the type noted an improved electric circuit for effecting a timed washing cycle including in sequence two washing steps, two rinsing steps and a drying step.

Further features of the invention pertain to the particular arrangement of the elements of the cyclic control circuit and of the circuit controller, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figure l is a front elevational view, partly broken away, of dishwashing apparatus embodying the present invention; Fig. 2 is a vertical sectional view of the dishwashing apparatus, taken in the direction of the arrows along the line 2-2 in Fig. 1; Fig. 3 is an enlarged fragmentary sectional view of the circuit controller incorporated in the control circuit of the dishwashing apparatus shown in Figs. 1 and 2, certain of the elements of the circuit controller being diagrammatically illustrated: and Fig. 4 is an electric diagram of the circuit controller and the circuit control arrangement incorporated in the dishwashing apparatus shown in Figs. 1 and 2.

Referring now to Figs. 1 and 2 of the drawings, there is generally illustrated dishwashing apparatus ill of the character of that disclosed in the previously mentioned Stoddard application and incorporating a cyclic control circuit embodying the features of the present invention. The dishwashing apparatus II) is of the gasketless-door front-opening type including a cabinet H housing a substantially vertically disposed vat II, the cabinet H and the vat l2 having substantially aligned front openings that are closed by a front door IS. The front door It is pivotally mounted adjacent to the lower edge thereof within the lower portion of the vat l2 and is movable between a substantially vertical closed position and a substantially horizontal open position. Also the dishwashing apparatus ill comprises movable rack structure, not shown, that is adapted to support dishes and other utensils within the vat I! for washing purposes, the rack structure being movable into and out of the vat i2 through the front openings when the door I! occupies its open position. An impeller I4 is arranged within a. sump Ii formed in the lower portion of the vat l2 and is rotated by an associated electric operating motor I6 for the purpose of producing a washing action within the vat I! when the door l3 occupies its closed position and washing liquid is contained in the sump For the purpose of supplying washing liquid to the vat I! there is provided an inlet conduit I! connected to a suitable source of washing liquid such, for example. as a hot water tank. The inlet conduit l'l communicates with the inlet port of an inlet valve ill of the solenoid controlled type; and the outlet port of the inlet valve l8 communicates with a conduit Is that is connected to a spraying device 2|! arranged in a depression 2! formed substantially centrally within the top wall of the vat l2. The inlet valve i8 is of the fast-opening. slow-closing type, being governed by an associated dashpot so as to prevent water hammer in the plumbing communicating with the inlet conduit H. The inlet valve IB is normally biased to its closed position, and when the solenoid l8 thereof is energized it is operated into its open position in order that washing liquid may be supplied from the inlet conduit I! to the spraying device 20, whereby the washing liquid is sprayed downwardly from the top of the vat l2 through the rack structure, not shown, and accumulates in the sump I5. Subsequently, when the solenoid ill of the inlet valve i8 is tie-energized it moves slowly from its open position to its closed position in order to cut of! the supply of washing liquid from the inlet conduit IT to the spraying device 20.

For the purpose of controlling the retention of washing liquid in the sump l5, there is provided a drain mechanism or valve 22 of the solenoid controlled type. The drain valve 22 comprises a flexible conduit 23, one end of which communicates with a drain fixture 24 provided in the lower portion of the sump l5, and the other end of which communicates with a drain conduit 25 that is connected via a trap, or the like, not shown. to drain plumbing, not shown. The flexible conduit 23 is normally biased into its lower position in order to place the interior of the sump I5 into draining communication with the drain conduit 25 so that any washing liquid accumulating in the sump I5 runs through the flexible conduit 23 into the drain conduit 25; and when the solenoid 22' thereof is energized the flexible conduit 23 is elevated into its upper position in order to cut off the draining communication between the interior of the sump I5 and the drain conduit 25 so that washing liquid may be retained in the sump I5. Subsequently, when the solenoid 22' is de-energized the drain valve 22 is returned to its draining position in order to effect draining of the washing liquid from the sump I5.

For the purpose of effecting drying of the dishes and other utensils supported by the rack structure, not shown, within the vat I2, there is provided a heating unit or element 26 that is preferably of the sheathed resistance conductor type. The heating element 26 is disposed in the lower portion of the vat I2 and in surrounding relation with respect to the impeller I4 so that air blown by the blades of the rotating impeller I4 contacts the heating element 26 and then moves upwardly into the vat I2 through the dishes and other utensils supported by the rack structure, not shown.

The lower portion of the door I3 carries a detergent cup 25 opening toward the interior of the vat I2 and adapted to receive a charge of detergent. Preferably, the detergent that is employed is of the type sold under the trade name Calgonite" that comprises about 40 per cent sodium hexametaphosphate and 60 per cent sodium metasilicate.

For the purpose of effecting coordinated operation of the operating motor I6, the inlet valve I8, the drain valve 22 and the heating element 26, so that a washing cycle, including predetermined spraying, washing. rinsing and drying steps, is carried out, a circuit controller 36 is incorporated in the dishwashing apparatus I6, the circuit controller 36 being arranged in the upper left-hand front portion of the dishwashing apparatus I6 and disposed between the adjacent left-hand side wall of the cabinet I I and the adjacent left-hand side wall of the vat I2. Of course, the circuit controller 36 is arranged exteriorly of the vat I2 and is appropriately wired in a circuit control network, including the operating motor I6, the solenoids I8 and 22', the heating element 26, a measuring coil or relay R46 and a door switch S4I. The measuring coil R46 is suitably supported within the cabinet I I exteriorly of the vat I2 and is of the marginal type, being provided with an armature, not shown, controlling a pair of contacts 4i. As indicated in Fig. 2, the door switch S4I may be carried adjacent to the front lower portion of the upstanding ledge disposed adjacent to the front opening provided into the vat I2 and in operative relation with respect to the door I3. More particularly, when the door I3 is respectively moved to its closed and opened positions, the door switch SM is respectively operated to its closed and opened positions. Finally, the circuit network comprises a source of current supply that may be of 115 volts 60 cycle A. C.

As best shown in Figs. 1 and 3 the circuit control 36 is of the combination manual and timer controlled type and comprises a front supporting plate 5| that is carried by the cabinet ll rearwardly of the extreme front wall thereof. The front plate BI is provided with a casing 52 detachably secured thereto, as well as a supporting bracket 53. A first rotatable shaft 54 is suitably journalled within the front plate 5| and in the bracket 53 and projects forwardly through a hole provided in the front wall of the cabinet II to the exterior. A manual control knob 55 is removably secured to the extreme front end of the shaft 54 and carries a pointer 56 that cooperates with a trim ring 51 secured upon the outer surface of the front wall of the cabinet II. The trim ring 5'] carries indicia cooperating with the pointer 56 and including the off index 56 and the on" index 59. Also the circuit controller 36 comprises a second rotatable shaft 66 and a stub shaft 6 I. The stub shaft 6| is suitably journalled in the front plate 5I and in the bracket 53, and the second shaft 60 constitutes a sleeve journalled on the stub shaft 6|. The shafts 66 and 6| are disposed above the shaft 54 and carry a friction clutch indicated at 62. The details of the friction clutch 62 are not shown but the adjacent face plates thereof are urged into frictional engagement with each other and are respectively rigidly secured to the shafts 66 and 6| for a purpose more fully explained hereinafter. The

shafts

54 and 66 are interconnected by speed-change gearing including two meshed

pinions

63 and 64 respectively rigidly secured thereto. The pinion 63 secured to the shaft 54 has precisely N times as many teeth as the pinion 64 secured to the shaft 66, where N equals to 3. Accordingly, the gearing effects a 1:3 speed ratio between the

shafts

54 and 60; whereby one revolution of the shaft 54 effects three revolutions of the shaft 66 and one revolution of the shaft 66 effects V, revolution of the shaft 54. Further, the circuit controller 36 comprises a timer motor unit 65 of the electro-responsive type that is carried by the bracket 53. The timer motor unit 65 may be of the "Telechron type including a motor proper 66 and a gear box 61 housing the usual speed re.- duction gearing, the speed reduction gearing housed within the gear box 61 interconnecting the stub shaft 6| and the motor proper 66. The gearing within the gear box 61 is so constructed and arranged that when the motor proper 66 is energized from the volts 60 cycle A. C. source the stub shaft BI is rotated at a speed of precisely three revolutions per hour.

In view of the foregoing description of the circuit controller 36. it will be understood that the shaft 54 may be manually rotated by the manual control knob 55 in order to effect rotation of the shaft 66 through the gearing 63-64; however. this rotation of the shaft 66 is not imparted to the stub shaft 6I directly connected by the gearing in the gear box 61 to the motor proper 66, the friction clutch 62 accommodating relative rotation between the shaft 66 and the stub shaft 6| by slipping action. On the other hand, when the motor proper 66 is energized, the stub shaft 6I is rotated at three revolutions per hour through the gearing in the gear box 61 and drives the shaft 66 through the friction clutch 62 at the speed noted. The consequent rotation of the shaft 66 at three revolutions per hour effects rotation of the shaft 54 at one revolution per hour by virtue of the gearing 64-63 interposed therebetween. Accordingly, operation of the motor proper 66 is normally effective to rotate the shaft 60 at three revolutions per hour in the counterclockwise direction and to rotate the shaft 54 at one revolution per hour in the clockwise direction as viewed in Fig. 1. The shaft 54 comprises an "oil" position and an on" position respectively corresponding to the "off and "on

indicia

54 and 59 respectively carried by the trim ring 51 and cooperating with the pointer 56 provided on the manual control knob 55. In the arrangement the on" index 59 is disposed slightly more than 60 degrees in the clockwise direction from the "off" index 58 so that when the manual control knob 55 is grasped and rotated in the clockwise direction through this angle slightly greater than 60 degrees, the pointer 58 is moved from its normal position cooperating with the off index II into an advanced position cooperating with the "on" index 59. As explained more fully hereinafter, the motor proper 66 is energized at this time, whereby the stub shaft Bi and the shaft 6|) are driven at the previously noted speed in the counterclockwise direction effecting further rotation of the shaft 54 in the clockwise direction. Specifically, the shaft 54 is further rotated at the speed of one revolution per hour from its "on control position in the clockwise direction back into its ffoif control position, whereby the pointer iii carried by the manual control knob 55 again cooperates with the off index 58 provided on the trim ring 56. Thus, it will be understood that after the shaft 54 is rotated from its oif" control position into its "on control position in the clockwise direction by the manual control knob 55 it is automatically rotated further in the clockwise direction back into its off control position by the motor proper 86 in a time interval slightly less than 50 minutes.

Of course, the shaft 54 comprises a plurality of control positions angularly disposed between its "on" control position and its "off control position, through which the shaft 54 proceeds sequentially as it is rotated in the clockwise direction. Also the shaft 50 comprises a plurality of angularly disposed control positions through which it proceeds three times incident to one complete revolution of the shaft 54 as a consequence of the gearing 83-64 interconnecting the shafts 54 and Gil. Two insulating cams respectively indicated at Cl and C2 are rigidly secured to the shaft 54 and respectively cooperate with two sets of switch springs diagrammatically illustrated at SI and S2. Similarly, two insulating cams respectively indicated at C3 and C4 are rigidly secured to the shaft 80 and respectively cooperate with two sets of switch springs diagrammatically illustrated at $3 and S4. The contacts j'X and "Y of the timer switch Si may be referred to as timer contacts; and the contacts "1" and 2" of each of the control switches S2 and S3, as well as the contacts of the control switch 84, may be referred to as switching contacts. Of course. in the timer switch S1, the timer contacts "X are closed before the timer contacts Y, and the timer con tacts "Y" are opened before the timer contacts "X, in the two movements of the main spring thereof. Finally, each of the control switches S2 and S3 is of the single-pole double-throw type.

The construction and arrangement of the circult controller 30 is disclosed and claimed in the copending divisional application of Douglas F. Illian, Serial No. 247,866, filed September 22. 1951.

The connection and arrangement of the control network for the various elements of the dishwashlng apparatus It will best be understood by reference to Fig. 4, wherein there is illustrated diagrammatically both the elements mentioned. as well as a time-sequence operating chart therefor indicating the coordinate controls exercised by the cams CI to C4, inclusive, upon the ease elated sets of switch springs SI to S4, inclusive. In the circuit network it is assumed that the negative line conductor H of the source of current supply is connected to ground potential and that the positive line conductor 12 of the source of current supply is insulated from ground potential.

When the dishwashing apparatus ill is at rest the manual control knob 55 occupies the position illustrated in Fig. 1, whereby the pointer 56 carried by the manual control knob 55 registers with the legend "off" carried by the trim ring 51 and the shaft 54 occupies its normal off position and the shaft Bll occupies its normal position. At this time the cam CI governs the set of switch springs SI to effect opening of the contacts X" and Y; while the cam C2 governs the set of switch springs S2 to effect opening of the contacts 1" and "2." Similarly, the cam CI govems the set of switch springs S3 to effect respective closing and opening of the contacts "1" and 2; while the cam C4 governs the set of switch springs S4 to effect closing of the associated contacts.

Considering now the cycle of operation of the dishwashing apparatus ill, the person loads the dishes and other utensils into the rack structure. not shown, and moves the rack structure into the vat l2, and then places a charge of detergent into the detergent cup 19. The person then moves the door 13 from its open position into its closed position effecting closure of the door switch S41, and then rotates the manual control knob 55 in the clockwise direction from its "off" position into its "on position. When the manual control knob 58 is thus rotated in the clockwise direction the shaft 54 is rotated in the clockwise direction and the shaft Iill is rotated in the counterclockwise direction. As indicated diagrammatically in Fig. 4, all of the control cams CI to C4, inclusive. are moved toward the left with respect to the associated sets of switch springs Si to S4, respectively. During this preliminary rotation of the shaft 54 in the clock wise direction from its "off position into its on" position, the control cams C3 and C4 respectively operate the sets of switch springs 83 and S4; however, without effect, since the set of switch springs S2 retains both of the contacts 1 and "2 thereof in their open positions; this ineffective operation of the sets of switch springs S3 and Si by the respectively associated cams Cl and C4 being brought about by virtue of the fact that the shaft is rotated slightly greater than degrees while the shaft 54 is rotated slightly greater than 60 degrees. The ineffective controls of the cams C3 and C4 with respect to the sets of switch springs S3 and S4, respectively, are indicated in dotted lines on the left-hand side and on the right-hand side of the effective control thereof indicated in solid lines, as explained more fully hereinafter. When the shaft 54 is rotated into its on" position, slightly over 60 degrees in the clockwise direction from its "off position, the cams Cl and C2 respectively operate the sets of switch springs SI and SI. Specifically, at this time, in the set of switch springs SI. the lowermost spring engages the highest portion of the cam Cl effecting closure of the contacts X" and Y"; and in the set of switch springs S2. the intermediate spring engages the lowest portion of the cam C2 effecting closure of the contacts "1. Also, at this time, in the set of switch springs 84, the intermediate spring engages the low portion of the cam C3 effecting respective closure and opening of the contacts "1" and 2"; and in the set of switch springs S4, the upper spring engages the high portion of the cam C4 eflecting opening of the associated contacts. In the set switch springs SI, when the contacts "Y are thus closed, a direct circuit, including the control conductor 14, the contacts "1 of the set of switch springs S3, the control conductor 10 and the door switch S, is completed across the line conductors 1| and I2 for initiating operation of the operating motor I0. Also, in the set of switch springs SI, when the contacts X" are thus closed, a circuit, including the control conductors l and 13 and the door switch SM. is completed across the line conductors 1| and 12 for initiatin operation of the timer motor 66. Upon operating, the operating motor I0 rotates the impeller I4 in the counterclockwise direction as viewed from the top of the vet I2. Upon operating, the timer motor 80 rotates, through the gearing in the gear box 61. the stub shaft 6| in the counterclockwis direction, whereby the shaft 80 is rotated in the counterclockwise direction through the friction clutch 02, effecting continued rotation 01 the shaft 54 in the clockwise direction from its on" position by virtue of the gearing 04-43. As previously noted the shaft 60 is rotated at a speed of three revolutions per hour while the shaft 54 is rotated at a speed of one revolution per hour; whereby during the next succeeding 11'70 seconds the cams C3 and C4 bring about eiiective selective operations of the respective sets of switch springs S3 and S4, as explained more fully below.

After an elapsed time interval of approximately 90 seconds, in the set of switch springs S3, the intermediate spring engages the high portion of the cam C3 eifecting opening of the contacts 1 and closing of the contacts 2. When the contacts "1 in the set of switch springs S3 are thus opened, the previously traced direct circuit for energizing the operating motor I6 is interrupted; and a normally completed shunt, including the control conductors I4 and 1B, for short-circuiting the measuring coil R40 is interrupted; whereby the measuring coil R40 is inserted in series circuit relation with the operating motor Hi. This series circuit for the operating motor and the measuring coil R40 extends from the control conductor I4 via the operating motor I0, the measuring coil R40, and the contacts Y in the set of switch springs SI to the negative line conductor II. Accordingly, the measuring coil R40 is now energized in series circuit relation with the operating motor I6 and meters the current drawn by the operating motor I0, which current is notexcessive at this time, since the operating motor I has already had an opportunity to gain full speed and there is no washing liquid in the sump I0 in the vat I2. In passing it is noted that the measuring coil R40 is of the marginal type and is not operated to open the contacts 4| when light currents are drawn by the operating motor I0, as explained more fully hereinafter.

Also, in the set of switch springs S3, when the contacts "2 are closed, a circuit, including the contacts "Y in the set of switch springs SI, the control conductors I4 and I9, the contacts 4|, the control conductor 11, the contacts 1 in the set of switch springs S2, and the control conductor II, is completed for energizing the inlet valve solenoid I0. This circuit for energizing the inlet valve solenoid I8 includes the closed contacts 4| 0! the measuring coil R40, as previously noted. When the inlet valve solenoid I0 is thus energized the inlet valve I8 is operated to its open position, as previously explained; whereby washing liquid is supplied from the inlet conduit II to the spraying device 20. The wash ing liquid sprays downwardly from the spraying device 20 through the dishes supported by the rack structure, not shown, and accumulates in the sump I5. This washing liquid drains from the sump I5 through the drain valve 22 and thence into the drain conduit 25. Some of the washing liquid in the sump It may be caught and flung upwardly and outwardly through the dishes supported by the rack structure, not shown. by the blades of the impeller I4, although this action is not considerable at this time since the drain valve 22 occupies its draining position. Accordingly, the dishes supported by the rack structure, not shown, in the vat l2 are subjected to a first spray step that is carried out through a time interval of approximately 30 seconds. i

At the conclusion of this first spray step the upper spring in the set of switch springs S4 engages the low portion of the cam C4 closing the associated contacts and completing a circuit, including the Y" contacts of the set of switch springs SI, the control conductors I4, 18 and 11, the contacts 1 of the set of switch springs S2 and the control conductor 13, for energizing the drain valve solenoid 22'. When the drain valve solenoid 22' is thus energized the drain valve 22 is operated to its non-draining position; whereby the washing liquid accumulating in the sum I5 is retained therein after the adjacent section of the flexible conduit 23 is first filled with the washing liquid. At this time the inlet valve I8 still occupies its open position and the operating motor IE is running. Accordingly, the washin liquid sprayed through the rack structure, not shown, from the spraying device 20 accumulates in the sump I5 since the drain valve 22 occupies its non-draining position. The washing liquid accumulating in the sump I5 of the vat I2 is caught by the blades of the impeller I4 and is flung upwardly and outwardly through the rack structure, not shown, and the dishes supported thereby against the walls of the vat i2 and the door I3 and again returns to the sump I5. The washing liquid as it is flung upwardly and outwardly has a generally rotary motion in the counterclockwise direction as viewed from the top of the vat I2 since the impeller I4 is rotated in this direction, as previously noted.

The supply of washing liquidfrom the spraying device 20 continues and as the quantity of washing liquid accumulating in the sump I5 increases, the load imposed upon the impeller I4 and consequently upon the operating motor I6 is gradually increased; whereby the current traversing the operating motor l6 and the measuring coil R40 is gradually increased. When a predetermined quantity of Washing liquid accumulates in the sump IS, a corresponding predetermined load is imposed upon the operating motor I6, whereby the current traversing the operating motor l6 and the measuring coil R40 reaches a predetermined value. When this current traversing the measuring coil R40 reaches the predetermined value mentioned indicating that the vat I2 now contains a full and predetermined quantity of washing liquid, the measuring coil R40 effects openin of the contacts 4|, since the measuring coil R40 is of of the marginal type. as previously noted. When the contacts 4| are thus opened, the circuit for energizing the inlet valve solenoid I is interrupted; whereby the inlet valve J0 is slowly returned to its closed position under the control of the associated dashpot. Shortly thereafter, the inlet valve "3 is completely closed cutting off the supply of washing liquid from the inlet conduit II to the spraying device 20.

Approximately 45 seconds after the drain valve 22 is operated to its non-draining position, the intermediate spring of the set of switch springs 83 engages the low portion of the cam C3 opening the contacts "2 and reclosing the contacts 13' When the contacts 2" of the set of switch springs S3 are thus opened, a further point in the circuit for energizing the inlet valve solenoid i0 is interrupted; and when the contacts "1" of the set of switch springs S3 are thus closed, the path for short-circuiting the measuring coil R40 is again completed, together with the direct circuit for operating the operating motor l6. Accordingly, the measuringcoil R40 is de-energized bringing about reclosure of the contacts 41; however, without effect at this time since the contacts 2 of the set of switch springs 83 are open. Thus the connections above-described provide a timed arrangement for effecting the de-energization 01 the inlet valve solenoid l8 and the consequent return of the inlet valve ill to its closed position in the event this result has not already been brought about by operation of the measuring coil R40 within the 45 seconds period mentioned.

The first washing step continues for a total time of approximately 330 seconds following the operation of the drain valve 22 to its non-draining position, and within this time interval and in response to the accumulation of a predetermined quantity of washin liquid in the sump i5, the charge of detergent contained in the detergent cup 20 is introduced into the washing liquid in order that the first washing step may be eflective to remove grease and other foreign materials from the dishes supported by the rack structure, not shown. The arrangement for introducing the detergent is disclosed in the copending application of Forrest A. Walker, Serial No. 57,4438, filed October 30, 1948, and is based upon the accumulation of a predetermined quantity of washing liquid in the sump l5, whereby the washing liquid accumulating in the sump I is flushed or washed into the detergent cup 29 carried by the inner wall of the door l3 causing the detergent to be washed into the body of washing liquid contained in the vat l2. This introduction of the detergent into the washing liquid is accomplished shortly following the operation of the drain valve 22 to its non-draining position so that the detergent is present in the washing liquid during a substantial part of the time interval of the first washing step.

At the conclusion of the first washing step the upper spring of the set of switch springs 84 engages the high portion of the cam C4 opening the associated contacts and interrupting the circuit for energizing the drain valve solenoid 22'; whereby the drain valve 22 is returned to its draining position. At this time washing liquid and the carried detergent drain from the sump into the drain conduit 25. The washing liquid contained in the sump II is drained in a very short interval oi time; and approximately 45 seconds after the drain valve 22 is operated to its draining position the intermediate spring of the set or switch springs 83 engages the high portion of the cam C8 again opening the contacts 1 and reclosing the contacts 2. When the contacts 1" are thus again opened the measuring coil R40 is again inserted in series with the operating motor l6; and when the contacts 2 are reclosed the inlet valve solenoid I8 is again energized; all in the manner previously explained. At this time the inlet valve I0 is operated to its open position effecting the supply of washing liquid from the liquid supply conduit I! to the spraying device 20; whereby the dishes supported by the rack structure, not shown, are again sprayed and the washing liquid accumulating in the sump i5 drains through the drain valve 22 in its draining position and thence into the drain conduit 25. This second spray step is carried out for a time interval of approximately 10 seconds; whereupon the upper spring of the set of switch spring S4 engages the lower portion of the cam C4 reclosing the associated contacts and effecting re-energizatlon of the drain valve solenoid 22'. The drain valve 22 is again operated to its non-draining position causing the washing liquid to be retained in the sump l5, initiating a second washing step.

The second washing step proceeds in the manner of the first washing step described above; whereby the inlet valve 18 is subsequently operated to its closed position under the control of the measuring coil R40 dependent upon the load upon the operating motor IE, or under the control of the cam C3 and the associated set of switch springs S3; all in the manner previously explained. In any case. after a time interval of approximately 45 seconds following operation of the drain valve 22 to its non-draining position the intermediate spring of the set of switch springs S3 engages the low portion of the cam C3 opening the contacts 2" and closing the contacts 1 in order positively to insure de-energization of the inlet valve solenoid l8 and short-circuiting of the measuring coil R40. At this time the inlet valve l8 occupies its closed position and the drain valve 22 oocupies its non-draining position; whereby the second washing step continues in the manner previously explained. The second washing step continues for a time interval of approximately 330 seconds following operation of the drain valve 22 to its non-draining position; whereupon, the upper spring of the set of switch springs S4 engages the high portion of the cam C4 opening the associated contacts and effecting de-energization of the drain valve solenoid 22' and the consequent operation of the drain valve 22 into its draining position.

The washing liquid accumulated in the sump i5 is drained into the drain conduit 25 in the manner previously explained in a very short time interval; and approximately 45 seconds after the drain valve 22 is operated into its draining position the intermediate spring of the set of switch springs S3 engages the high portion of the cam C3 again opening the contacts "1 and reclosing the contacts 2. Opening of the contacts "1 effects reinsertion of the measuring coil R40 in series with the operating motor l6; and reclosure of the contacts 2 eflects reenergization of the inlet valve solenoid I8. The inlet valve I8 is again operated to its open position in order to initiate a third spray step. The washing liquid supplied from the liquid supply conduit H to the spraying device 20 is sprayed through the dishes supported by the rack structure. not shown. and is drained from the sump I6 into the drain conduit 25. This third spray step continues through a time interval of 10 seconds following operation the inlet valve it to its open position; whereupon, the upper spring of the set 0! switch springs S4 re-engages the low portion of the cam C4 reclosing the associated contacts and the circuit for energizing the drain valve solenoid 22'. The drain valve 22 is operated to its non-draining position in order again to cause washing liquid to accumulate in the sump l5, initiating a first rinsing ste T he first rinsing step proceeds in a manner substantially identical to the first washing step described above; whereby the inlet valve I8 is subsequently operated to its closed position under the control of the measuring coil R40 dependent upon the load upon the operating motor It, or under the control of the cam C3 and the associated set 01' switch springs S3; all in the manner previously explained. In any case. after a time interval of approximately 45 seconds following operation of the drain valve 22 to its nondraining position, the intermediate spring of the set of switch springs S3 engages the low portion 01' the control cam C3 effecting opening of the contacts "2 and closing of the contacts "1 in order positively to insure de-energization oi the inlet valve solenoid l8 and short-circuiting of the measuring coil R40. At the time the inlet valve 18 occupies its closed position and the drain valve 22 occupies its non-draining position; whereby the first rinsing step continues for a time interval of approximately 90 seconds following the operation of the drain valve 22 to its non-draining position; whereupon, the upper spring or the set of switch springs S4 engages the high portion oi the cam C4 opening the associated contacts and effecting de-energization oi the drain valve solenoid 22' and the consequent return oi the drain valve 22 to its draintion.

".lh g washing liquid accumulated in the sump i5 is drained into the drain conduit 25 in the manner previously explained in a short time interval; and approximately 45 seconds after the drain valve 22 is operated into its draining position, the intermediate spring of the set of switch springs S3 engages the high portion of the cam C3 opening the contacts "1 and closing the contacts 2 in order to eiiect insertion of the measuring coil B40 in series with the operating motor l8 and energization of the inlet valve solenoid la. The inlet valve I8 is again operated to its open position in order to initiate a fourth spray step. The washing liquid supplied from the liquid supply pipe H to the spraying device 20 is sprayed through the dishes supported by the rack structure. not shown, and is drained from the sump 15 to the drain conduit 25. This fourth spray continues through a time interval of approximately 10 seconds following operation of the inlet valve It to its open position; whereupon the upper spring of the set of switch springs 84 engages the low portion of the cam 04 closing the associated contacts and effecting energization of the drain valve solenoid 22. The drain valve 22 is operated to its non-draining position in order again to cause washing liquid to accumulate in the sump l5, initiating a second rinsing step.

The second rinsing step proceeds in a manner identical to the first rinsing step described above; whereby the inlet valve I8 is subsequently operated to its closed position under the control oi the measuring coil R40 dependent upon the load 12 upon the operating motor It, or under the control of the cam C3 and the associated set of switch springs S3; all in the manner previously explained. In any case, after a time interval of approximately 45 seconds following operation of the drain valve 22 into its non-drainin position. the intermediate spring of the set of switch springs S3 engages the low portion of the cam C3 opening the contacts 2" and closing the contacts 1" in order positively to insure de-energization of the inlet valve solenoid l8 and short-circuiting of th measuring coil R40. At this time the inlet valve it occupies its closed position and the drain valve 22 occupies its non-draining position; whereby the second rinsing step continues for a time interval of approximately seconds following operation of the drain valve 22 to its non-draining position; whereupon the upper spring of the set of switch springs S4 engages the high portion of the cam C4 opening the associated contacts in order to eiiect de-energization of the drain valve solenoid 22' and the consequent return of the drain valve 22 to its draining position.

The washing liquid accumulated in the sump Ii is drained into the drain conduit 25 in the manner previously explained in a short time interval; and approximately 45 seconds after the drain valve 22 is operated to its draining position the intermediate spring of the set of switch springs S2 engages the highest portion of the cam C2 openin the contacts 1 and closing the contacts 2. When the contacts l of the set of switch springs S2 are thus opened the common point in the circuit for energizing the inlet valve solenoid l8 and the drain valve solenoid 22' is interrupted, thereby positively to insure that the inlet valve It occupies its closed position and the drain valve 22 occupies its draining position in the remainder of the washing cycle. In other words, the operation of the set of switch springs S2 to open the contacts 1 positively disables further effective control of the sets of switch springs S3 and S4 notwithstanding further operatoin thereof by the respective cams C3 and C4. In the set of switch springs S2, closure of the contacts "2 completes a circuit for energizing the heating element 26 that includes the control conductors I3, 15' and I5 and the X" contacts of the set of switch springs SI; whereby heat produced by the heating element 26 in the vat i2 is circulated in the vat l2 by the blades of the impeller i4 since operation of the operating motor I8 is continued at this time. The hot air circulated in the vat l2 by the impeller I4 is directed into contact with and through the dishes supported by the rack structure, not shown, and thence back into contact with the heating element 26.

This initial dryin step is continued for a time interval of approximately 1200 seconds; whereupon the lowermost spring of the set of switch springs Si engages the intermediate portion of the cam Cl effecting opening of the contacts Y" while the contacts X" are retained closed. Opening of the contacts Y of the set of switch springs Si interrupts the circuit for operating the operating motor l6; while the closed contacts "X" of the set of switch springs Si retains completed the circuit for energizing the heating element 26. Accordingly, the operating motor l6 stops, arresting the rotation of the impeller l4, while the supply of heat to the heating element 26 continues. Thus drying of the dishes supported by the rack structure, not shown. continues through a final drying step after operation oi the 13 impeller H has been arrested. The final drying step continues for a time interval of approximately 600 seconds; whereupon the lowermost spring of the set of switch springs Si engages the lowest portion of the cam CI opening the contacts X"; and the intermediate spring of the set of switch springs S2 engages the intermediate portion of the cam C2 opening the contacts 2. Opening of the contacts X of the set of switch springs SI interrupts the circuit for energizing the heating element 26 and interrupts the operating circuit for the timer motor 55. Also, opening of the contacts "2 of the set of switch springs S2 interrupts a further point in the circuit for energizing the heating element 26, whereby both terminals of the heating element 26 are disconnected at this time from the line conductors H and I2 of the source of current supply.

At this time the shaft 54 of the circuit controller 30 has been rotated from its on position in the clockwise direction back into its off position; operation of the circuit controller 30 has been arrested; and the washing cycle of the dishwashing apparatus It has been completed. Thus it will be understood that when the manual control knob 55 of the circuit controller 30 is rotated from its off" position, slightly greater than 60 degrees in the clockwise direction into its on position, further operation of the circuit controller ill is automatically initiated under the control of the timer motor 66. More particularly, the timer motor 66 eifects continued rotation of the manual control knob 55 in the clockwise direction from its on position back into its "off position, whereby operation of the circuit controller 30 is automatically arrested. As the shaft 54 is rotated from its on position back into its "01! position in the clockwise direction, it is rotated sequentially through the different control positions thereof causing the cams Cl and C2 to effect the operations of the sets of switch springs SI and S2, respectively, as described above. Also, the shaft 80 is rotated in the counterclockwise direction causing the cams C3 and C4 to effect the sequential operations of the sets of switch springs S8 and S4, respectively, as described above.

Since the shaft 60 is rotated three revolutions in the counterclockwise direction while the shaft 54 is rotated only one revolution in the clockwise direction, noncontrolling operations by the cams C3 and C4 of the sets of switch springs S3 and S4, respectively, are effected at the beginning and at the end of the washing cycle; however, without effect, since the actual control exerted by the sets of switch springs S3 and S4 is negated by the set of switch springs S2 except during one revolution of the shaft ill in the intermediate portion of the washing cycle. More particularly, the sets of switch springs S3 and S4 are rendered operative to eilect controls only when the set of switch springs S2 is operated to close the contacts "1"; which circumstance is present in the cycle only during rotation of the shaft 54 through the segment of its revolution between 60 and 180 degrees thereof from its "off position. This rotation of the shaft 54 through 120 degrees corresponds to a. complete rotation of the shaft 60 through 360 degrees, as clearly indicated in Fig. 4. Following this rotation of the shafts 8-0 and i4 and when the shaft 54 reaches its 180 degree position, the cam C2 operates the set of switch springs S2 in order to open the contacts "1, thereby again negating operation of the sets of switch springs S3 and S4.

This arrangement is very advantageous as it permits utilization of the complete 360 degrees of periphery of the cams C3 and C4 to effect the operations of the sets of switch springs S3 and S4, respectively, during the corresponding degrees of rotation of the cams Cl and C2. Thus the arrangement permits the desired fine and accurate controls of the inlet valve solenoid II and the drain valve solenoid 22' repeatedly in the intermediate 1170 seconds within the washing cycle where these controls are required. Thus the cams CI to C4, inclusive, efiect coordinate operations of the sets of switch springs SI to S4, inclusive, in order to effect the automatic washing cycle of the dishwashing apparatus ll) through the various spraying, washin rinsing and drying steps as explained above.

As previously explained, the friction clutch l2 interposed between the shafts GI) and SI permits rotation of the shaft 60 in either direction by the manual control knob 55 with respect to the stub shaft til at any time and independently of the timer motor 58 so that any one or more of the steps in the above-described washing cycle may be selectively omitted or repeated by appropriate manual rotation of the manual control knob 56 in the proper direction. For example, the final drying step may be omitted from the abovedescribed washing cycle by rotating the manual control knob 55 in the clockwise direction back into its off" position when the cam C2 first operates the set of switch springs S2 to close the contacts "2, thereby reducing the length of the washing cycle by approximately 30 minutes. This facility is especially useful when it is desired to wash a number of loads of dishes and automatic drying thereof is not important to the operator, or hand-drying thereof is particularly wished by the operator.

During the operation of the dishwashing apparatus H) in the timed washing cycle above described, the door it must be retained in its closed position as previously explained in order to retain the door switch S4! in its closed position. as it will be observed that the door switch S4! occupies an interlock position in the control network, and that any time the door It is operated to its open position, the door switch S is operated to its open position arresting all operations of the dishwashing apparatus l0. Finally at the conclusion of the timed washing cycle the dishes supported by the rack structure, not shown, have not only been thoroughly washed and rinsed, but they have also been dried. Subsequently, the door I3 may be moved from its closed position into its open position and the rack structure, not shown, may be moved out of the vat l2 over the door l3 in its open position so that the dishes may be removed from the rack structure and placed in a kitchen cabinet, or the like, if desired.

In view of the foregoing it is apparent there has been provided in dishwashing apparatus an improved cycle control circuit obtaining an improved cycle of operation of the electro-responsive elements thereof that permits flexibility of operation and achieves accurate and positive response. While the circuit controller of improved construction and arrangement has been disclosed in the cyclic control circuit of the dishwashing apparatus, it will be understood that it is generally useful in other program selecting systems, such, for example, as in clothes washing apparatus, Or in other apparatus requiring a prescribed program or cycle of predetermined operations.

While there has been described what is at present considered to be the preferred embodiment of 15 the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In dishwashing apparatus including a vat, an inlet valve for controlling the admission of washing fluid into said vat, said inlet valve being normally biased into its closed position, a first solenoid for operating said inlet valve into its open position, a drain valve for controlling the draining oi washing fiuid from said vat, said drain valve being normally biased into its open position, a second solenoid for operating said drain valve into its closed position, an electric drive motor for circulating washing fluid in said vat, and an electric heater for drying dishes in said vat; a circuit control network comprising a source of current supply, a rotatable circuit controller having an off position and an on position and a plurality of control positions and rotatable continuously from its ofi position into its on position and then through its control positions back into its off position, a manually rotatable member for rotating said circuit controller from its oil position into its on position, means including an electric timer motor for rotating said circuit controller at a predetermined rate from its on position through its control positions back into its 03 position, first and second pairs of timer contacts, means responsive to rotation of said circuit controller into its on position for closing first said first pair of timer contacts and then said second pair of timer contacts and responsive to rotation of said circuit controller into its oif position for opening first said second pair of timer contacts and then said first pair of timer contacts, a timer circuit for selectively operating said timer motor and including said source and said first pair of timer contacts, a plurality of pairs of switching contacts, means responsive to rotation of said circuit controller through its various control positions for selectively opening and closing said pairs of switching contacts, a first control circuit for selectively operating said first solenoid and including said source and said second pair of timer contacts and a first of said pairs 01 switching contacts, a second control circuit for selectively operating said second solenoid and including said source and said second pair of timer contacts and a second 01' said pairs of switching contacts, a third control circuit for selectively operating said drive motor and including said source and said second pair of timer contacts, and a fourth control circuit for selectively energizing said heater and including said source and said first pair of timer contacts.

2. In dlshwashing apparatus including a vat, an inlet valve for controlling the admission of washing fiuid into said vat, said inlet valve being normally biased into its closed position, a first solenoid for operating said inlet valve into its open position, a drain valve for controlling the draining of washing fluid from said vat, said drain valve being normally biased into its open position, a second solenoid for operating said drain valve into its closed position, an electric drive motor for circulating washing fiuid in said vat, and an electric heater for drying dishes in said vat; a circuit control network comprising a source of current supply, a rotatable circuit controller having an off position and an on position and a plurality oi control positions and rotatable continuously from its ofi position into its on position and then through its control positions back into its oil position, a manually rotatable member for rotating said circuit controller from its ofi po-, sition into its on position, means including an electric timer motor for rotating said circuit controller at a predetermined rate from its on position through its control positions back into its off position, first and second pairs of timer contacts. means responsive to rotation of said circuit controller into its on position for closing first said first pair of timer contacts and then said second pair of timer contacts and responsive to rotation of said circuit controller into a given one 01' its control positions for opening said second pair of timer contacts and responsive to rotation 01' said circuit controller into its off position for opening said first pair of timer contacts, a timer circuit for selectively operating said timer motor and including said source and said first pair of time: contacts, a plurality of pairs of switching contacts, means responsive to rotation of said circuit controller through its various control positions for selectively opening and closing said pairs of switching contacts, a first control circuit for selectively operating said first solenoid and including said source and said second pair of timer contacts and a first of said pairs of switching contacts, a second control circuit for selectively operating said second solenoid and including said source and said second pair of timer contacts and a second of said pairs of switching contacts, a third control circuit for selectively operating said drive motor and including said source and said second pair of timer contacts, and a fourth control circuit for selectively energizing said heater and including said source and said first pair of timer contacts.

3. In dishwashing apparatus including a vat, an inlet valve for controlling the admission of washing fluid into said vat, said inlet valve being normally biased into its closed position, a first solenoid for operating said inlet valve into its open position, a drain valve for controlling the draining of washing fiuid from said vat, said drain valve being normally biased into its open position, a second solenoid for operating said drain valve into its closed position, an electric drive motor for circulating washing fluid in said vat, and an electric heater for drying dishes in said vat; a circuit control network comprising a source of current supply, a rotatable circuit controller having an off position and an on position and a plurality of control positions and rotatable continuously from its oil. position into its on position and then through its control positions back into its off position, a manually rotatable memher for rotating said circuit controller from its of! position into its on position, means including an electric timer motor for rotating said circuit controller at a predetermined rate from its on position through its control positions back into its off position, a timer switch responsive to rotation of said circuit controller into its on position for connecting said timer motor to said source to initiate operation thereof and responsive to rotation of said circuit controller into its off position for disconnecting said timer motor from said source to arrest operation thereof, a double-throw switch having first and second contacts, a plurality of pairs of switching contacts, means responsive to rotation of said circuit controller through its various control positions for selectively operating said double-throw switdh and for selectively opening and closing said pairs of switching contacts, a first control circuit for 17 selectively operating said first solenoid and including said source and said first contacts of said double-throw switch and a first of said pairs of switching contacts, a second control circuit for selectively operating said second solenoid and including said source and said first contacts of said double-throw switch and a second of said pairs of switching contacts, a third control circuit for selectively operating said drive motor and including said source and said timer switch, and a fourth control circuit for selectively en ergizing said heater and including said source and said timer switch and said second contacts of said double-throw switch.

4. In dishwashing apparatus including a vat, an inlet valve for controlling the admission of washing fluid into said vat, said inlet valve being normally biased into its closed position, a first solenoid for operating said inlet valve into its open position, a drain valve for controlling the draining of washing fluid from said vat, said drain valve being normally biased into its open position, a second solenoid for operating said drain valve into its closed position, an electric drive motor for circulating washing fiuid in said vat, and an electric heater for drying dishes in said vat; a circuit control network comprising a source of current supply, a rotatable circuit controller having an off position and an on position and a plurality of control positions and rotatable continuously from its off position into its on position and then through its control positions back into its ofi position, a manually rotatable member for rotating said circuit controller from its of! position into its on position, means including an electric timer motor for rotating said circuit controller at a predetermined rate from its on position through its control positions back into its off position, a timer switch responsive to rotation of said circuit controller into its on position for connecting said timer motor to said source to initiate operation thereof and responsive to rotation of said circuit controller into its off position for disconnecting said timer motor from said source to arrest operation thereof, a double-throw switch having first and second contacts, a plurality of pairs of switching contacts, means responsive to rotation of said circuit controller through its various control positions for selectively operating said double-throw switch and for selectively opening and closing said pairs of switching contacts, a relay of the marginal type provided with a winding and back contacts, a first control circuit for selectively operating said first solenoid and including said source and said second contacts of said double-throw switch and said back contacts of said relay and a first oi said pairs of switching contacts, a second control circuit for selectively operating said second solenoid and including said source and said first pair of switching contacts and a second of said pairs of switching contacts, a third control circuit for selectively operating said drive motor and for selectively energizing said winding of said relay and including said source and said timer switch, a path for short-circuiting said winding 01' said relay and including said first contacts of said double-throw switch, and a fourth control circuit for selectively energizing said heater and including said source and said timer switch and a third of said pairs of switching contacts.

5. In dishwashing apparatus including a vat. an inlet valve for controlling the admission of washing fluid into said vat, said inlet valve being normally biased into its closed position, a first solenoid for operating said inlet valve into 18 its open position, a, drain valve for controlling the draining of washing fluid from said vat, said drain valve being normally biased into its open position, a second solenoid for operating said drain valve into its closed position, an electric drive motor for circulating washing fluid in said vat, and an electric heater for drying dishes in said vat; a circuit control network comprising a source of current supply, a rotatable circuit controller having an off position and an on position and a plurality of control positions and rotatable continuously from its oif position into its on position and then through its control positions back into its off position, a manually rotatable member for rotating said circuit controller from its off position into its on position, means including an electric timer motor for rotating said circuit controller at a predetermined rate from its on position through its control positions back into its off position, a timer switch responsive to rotation 01' said circuit controller into its on position for connecting said timer motor to said source to initiate operation thereof and responsive to rotation of said circuit controller into its oil position for disconnecting said timer motor from said source to arrest operation thereof, first and second double-throw switches each having first and second contacts, a pair of switching contacts, means responsive to rotation of said circuit controller through its various control positions for selectively operating said doublethrow switches and for selectively opening and closing said pair of switching contacts, a relay of the marginal type provided with a winding and back contacts, a first control circuit for selectively operating said first solenoid and including said source and said first contacts of said first double-throw switch and said back contacts 01 said relay and said second contacts of said second double-throw switch, a second control circuit for selectively operating said second solenoid and including said source and said first contacts of said first double-throw switch and said pair of switching contacts, a. third control circuit for selectively operating said drive motor and for selectively energizing said winding of said relay and including said source and said timer switch, a path for short-circuiting said winding of said relay and including said first contacts of said second double-throw switch, and a fourth control circuit for selectively energizing said heater and including said source and said timer switch and said second contacts of said first double-throw switch.

DOUGLAS F. ILLIAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,323,216 Cornwall et al Nov. 25, 1919 2,155,271 Jones Apr. 18, 1939 2,195,642 De Larm Apr. 2, 1940 2,217,705 Rataiczak et a1. Oct. 15, 1940 2,281,852 Messier May 5, 1942 2,295,057 Schumcrt Sept. 8, 1942 2,342,814 Miller Feb. 29, 1944 2,422,022 Koertge June 10, 1947 2,425,620v Kempton Aug. 12, 1947 FOREIGN PATENTS Number Country Date 584,827 Great Britain June 23, 1947