US2596693A - Dishwashing machine - Google Patents

Description

May 13, 1952 .J. F. R. KARLsTRoM ,6

DISK-{WASHING MACHINE Filed Oct. 4, 1950 4 Sheets-Sheet 1 I flag/ ara y' BY y 1952 J. F. R. KARLSTROIVI DISHWASHING MACHINE 4 Sheets-Sheet 3 Filed Oct. 4, 1950 Illailllll. n 'IIII'III'I 'IIIIIIII'IIA IIIII y 13, 1952 J. F. R. KARLSTROIVI 2,596,693

DISHWASHING MACHINE Filed Oct. 4, 1950 4 Sheets-Sheet 4 IN V EN TR.

Patented May 13, 1952 DISHWASHING MACHINE Johan Fredrik Robert Karlstrom,

Stockholm,

Sweden, assignor to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of Sweden Application October 4, 1950, Serial No. 188,317

(Cl. 134-412) V 11 Claims. 1

, This invention relates to dish-washing machines, and particularly to those in which the dishes to be washed are contained in a closed chamber in which a plurality of rotatingspinners or spraying devices are arranged. One of the objects of the invention is to provide, in a construction of this character, a plurality of such spinners or spraying devices, arranged in groups and adapted to be selectively and intermittently rotated while spraying, and while the spinners in the other groups are rotated but are not spraying.

Another object of the invention is to provide means by which the spinners in one group will be distributing the spraying fluid while those in another group will idly rotate and not spray, and to provide means for automatically causing the sprayers in one group to cease spraying and those in the other group to begin to spray, and thus alternately cause the several sprayer groups to spray the dishes contained in the machine.

The invention further contemplates the provision of an improved valve control by means of which the washing fluid supply is delivered to one group of the spraying instrumentalities for a.

given period of time and is then diverted to a second group, with this sequence repeated as long as the machine is in operation, and with means provided by which the periods of spraying operation of each group of spraying devices can be varied to meet washing requirements.

These and other objects are attained by the invention, a more particular description of which will hereinafter appear and be set forth in the claims forming a part of this specification.

In the accompanying drawings, wherein an illustrative embodiment of the invention is disclosed, Fig. 1 is a front elevation of the improved dishwasher, with parts in section and other parts broken away, to disclose construction; Fig. 2 is a sectional view, taken on the line 22 of Fig. 1, looking in the direction of the arrows; Fig. 2A is a view similar to Fig. l with the hinged front removed to illustrate both the top and bottom spraying devices; Fig. 3 is a sectional view in plan, of a modified structure; Fig. 4 is a sectional view of the automatic valve included as a part of the dishwasher mechanism; Fig. 5 is a sectional view, taken on the line 55 of Fig. 4, looking in the direction of the arrows; Fig. '6 is a sectional view, taken on the line 6-6 of Fig. 5, looking in the direction of the arrows; Fig. 7 is a sectional view of a portion of the mechanism shown in Fig. 6; Fig. 8 is a top plan view of the device shown in Fig. 7; Fig. 9 is a longitudinal sectional view through a modified form of valve, the view being taken on the line 9--9 of Fig. 11; Fig. 10 is a side elevational view of the valve shown in Fig. 9; Fig. 11 is a sectional View, taken on the line ll-ll of Fig. 10, looking in the direction of the arrows; and Fig. 12 is a sectional view, taken on the line |2I2 of Fig. 10, looking in the direction of the arrows.

Referring to the structure illustrated in Figs. 1 to 3 inclusive, l0 designates the housing or casing of a dishwashing-machine of a type and structure adapted for attachment to a wall or other suitable support. Such housing or casing 10 includes a hinged front door ll pivotallyattached to the housing by means of the hinges I2. Contained within the housing is a dishrack or wire basket I3 in which the dishes to be washed are placed, and located below this basket or rack, and near the bottom l5 of the housing in is a screen M. A similar screen, not shown, may be employed in the housing near the top or roof [6 of the housing.

Located below the lower screen I4 is a pair of rotatively-mounted spraying or rinsing devices, sometimes referred to in this art as spinners, each of which is generally indicated at H. Each spraying or rinsing device or spinner l1 consists of a three-arm spider 18 having a jet head l9 located centrally or axially of the spider. Both the spider l8 and the jet head H! are together rotatively mounted on a vertical axis in a bearing member 20, the bearing members for the lower spraying or rinsing device being securely attached to the bottom I 5 of the housing, on the outside of the same, and the bearings 20 for the upper spraying devices I! being similarly securely fastened to the top or roof 16 of the housing [0.

Each of the bearing members 20 is provided with supply passages for the washing and rinsing liquids, such passages being connected to pipes 2|, 22, 23 and 24 which extend from a valve generally indicated at 25 which is connected to a suitable source of water or other washing liquid, by the pipe indicated at 26. Each arm 21 of each spider I8 is provided withchanneled or serrated areas 28 which cooperate with liquidjets discharged from the jet heads.

The rotatable jet heads I9 have a plurality of openings (not shown) for discharging the liquid jets therefrom, and the arms 21 serve as jet defleeting means angularly movable relative to the jet heads l9 and about the axes of the latter for changing the direction of the jets. Accordingly, each of the arms 21 isformed with a series housing 31.

of serrations or grooves diagrammatically indicated at 28 which serve to change the direction of the jets in a multiplicity of directions, the arms being movable by the impact forces of the jets on the arms. The spraying devices are shown and described in my application Serial No. 740,585, filed April 10, 1947, and, if desired, reference may be had thereto for a detailed description of the spraying devices.

The hub or central part of each of the spiders I8 is provided with a pulley 29 formed on or attached to the hub thereof and by means of which the two pairs of rinsing or spraying devices |1, located at the top and bottomjrespectively of the housing Ill, are rotated, the devices in eachpair being connected by the drive belt 30. As seen in Fig. 2, the drive belt 35 is crossedin order to drive the two spraying or rinsing devices I1 in opposite directions. As an alternative, the two spraying or rinsing devicesin each pair may have their arms curved in opposite directions, in which event the drive belt need not be arranged in crossed position. As a substitute for the belt drive above described, suitable gearing may be employed for effecting rotation of the spraying means.

In the modified embodiment of the invention shown in Fig. 3, each of the rinsing or spraying devices consists of a straight pipe or tube 3| having a plurality of jet openings 32. In this embodiment, the belt need not be crossed, and

thejet openings 32 in the pipes or tubes 3| can be arranged angularly or obliquely so that the washing fluid forced through these openings will result in imparting a rotative movement to the spraying or rinsing devices in a manner known in this art.

The details of the valve generally indicated at are shown in detail in Figs. 4 to 8 inclusive. The'structure and operation of this valve is such that the same automatically and at predetermined intervals, directs the washing fluid to "'pairs of the spraying or rinsing devices H of the apparatus in a manner to be explained. The valve .25, as seen in Figs 1 and 4, is securely at .tached to the bottom of the housing It] by .means of two bolts 35' which connect the bottom l5 of thehousing with the bosses 36 of the valve The valve housing 31 is generally tubular in shape, and includes a longitudinally extending cylindrical chamber 38 which is formed with three laterally extending channels disposed at right angles to ,thechamber 38, as

,morecle'arly seen inFig. 5. The centralone of these channels, or that indicated at 38, con- .stitutes ,a supply conduit. The other two channels, indicated respectively at 43 and 4|, constitute discharge passages. The supply channel 39 is directed downwardly and is in communication with a chamber 42 in which a filter or strainer is contained, the same consisting of a body 43 of stainless or non-corrosive metallic wool. The filter body 43 is enclosed in a cylinder 44 having a perforated or foraminous ,top and bottom. The casing in which the chamber 42 is located is provided around its lower edge with a flange 45 to which is attached a pipe coupling 46 by means of the screws 41 or equivalent fastening elements. The pipe coupling 48 is formed with a part 4.8 having two passages indicated respectively at 49 and 50, and to which conduits 5| and 52 can be connected from a source of supply for the detergentor washing agent (not shown).

In order to effectively supply the flow of detergent or washing agent through the apparatus, the inner ends of the passages 49 and 50, and which open into the central passage 53 in the pipe coupling 46, are angularly or obliquely directed to be thus with and against the flow of the entering water from the supply pipe 26. In this manner the speed of the entering. water is employed to direct the detergent toward the spraying or rinsing devices. The supply pipe 26 from a source of water supply, is attached to the coupling 45, being connected thereto by the nipple 54' and being thus placed in communication with the central passage 53 extending through the coupling 43.

The channel 40 which is located above the axially-extending center line of the valve housing 31, has one end leading through the boss 55 formed on the valve housing 31, the boss 55 being connected to the pipe 2| that extends to one of the lower bearings 20. The opposite end of the channel 4|], located in the housing extension 55, is coupled tothe pipe 22 that extends to one of the upper bearings 2|i,as clearly seen in Fig. l. The channel 4| is located below the axial center line of the housing 31 and one end located in the boss 51 formed on the valve housing 31, said end being connected to the pipe 23 that extends to the second or right-hand lower bearing 20, while the opposite end of the channel 4|, located in the housing extension 58, is connected to the pipe 24 that is connected at its opposite end to the left-hand upper bearing 20.

Formed in the valve housing 31 is the chamber 38, which has its opposite ends closed by the closure plugs or caps 60. Said chamber 38 is in communication with the channels 40 and 4| by means of the passages 6| and 62 respectively which extend substantially parallel to the chamber 38. The passage 62 is arranged to be controlled by means of a needle valve, including the spindle 63, adjustable through the gland nut 64 and stuffing box 65, which parts are located in a sleeve 66 formed on and extending from the valve housing 31. One end of a lateral part 61 of thepassage 62 constitutes a seat for the tapered or pointed end of the needle valve spindle 63,

Within the chamber 38 are located two twoheadedpistons arranged for slidable movement in a manner to .be described. One of the. pistons generally indicated at 68 may be referred to as the operating piston, and that shown at 63 may be termed the reversing piston. The ope'ratingpiston 68 includes a spindle or shaft 10, at the opposite ends of which are locatedthe two heads 1| which are held in position on the spindle or shaft by the nuts 12 which hold the heads 1| clamped against shoulders formed on the spindle or shaft 15. A spring 14 is located between each of the heads 1| and a washer .15 which is slidable on the spindle orshaft 10. The sliding movement of the two washers 15 is limited by the reversing piston 69 and by the shoulders 16 formed on the spindle 16. The reversing piston 69 which slides on the spindle 10 and surrounds the spindle, includes two piston heads 11 preferably but not necessarily formed integrally with a central rod section 18. ,The piston heads 11 are hollow and at the bottom are formed with a number of apertures .19 constituting ports through these heads. The

at one side by' a conical portion 82.' The two dicated generally at 83 in Fig. 6, and shown in detail in Figs. 7 and 8, to lock the reversing piston in either of two positions, the stroke of the piston being equal to the distance between the two grooves 80.

. The locking device 83 shown in Figs. 6 to 8 inclusive, is located in a sleeve 84 formed on and extending angularly or obliquelyfrom the valve housing 31. This locking device includes a locking plunger 85, slidable within the sleeve 84 and spring-pressed toward the rod portion 18 by a coil spring 81 back by the nut 86..v The inner end of the locking piston 85 is forked to carry a rotatable roller 89 mounted on the shaft 90 extending across the forked end of the plunger 85.

In its locking positions, the roller 89, acting under the pressure of the coil spring 81, engages in one or the other of the grooves 85 of the piston rodportion 18. In order to minimize friction between the plunger 85 and the sleeve 84 in which it is slidably mounted, and also to prevent the plunger 85 from turning about its longitudinal axis, twoballs 9| are supported near the front part of the plunger 85. Grooves fitting the balls are provided in the walls of the sleeve 84. The rear end 92 of the plunger 85 is guided in the recess 93 in the threaded nut or closure plug 86, as clearly seen in Fig. 6.

From the foregoing, the operation of the valve will be readily understood. Reference is made to Figs. 4 and 5 wherein the valve is shown in operating position immediately prior to its reversing movement. The washing fluid enters the valve by passing through the supply pipe 26, thence through the strainer or filter body 43 and into the discharge channel 49, which is at this time opened by being to one side of the left piston head 11, and into the pipes 2| and 22 and to the respective spraying or rinsing devices H to which those pipes are connected, namely, the left-hand lower one and the right-hand upper one. The space in chamber 38 between the heads H of the operating piston becomes filled with the fluid by passage through the apertures I9 so that pressure on the inside of the operating piston and on the reversing piston is equal. The washing liquid then flows through the nozzles on'the rinsing or spraying heads I 9 toward the serrated portions 28 of the spinner arms 21' causing rotation of the spiders I8 and rinsing heads l9 carried thereby. This, of course, refers to the left-hand lower spider and the right-hand upper one. Due to the fact that these particular spider are coupled to their companions by the belts 30, it is obvious that the right-hand lower spider and the left-hand upper one will be caused to rotate or idle but not spray. Due to the resistance exerted in the pipes 2| and 22 and their rinsing or spraying devices I! respectively, a counter-pressure occurs causing the washing liquid to flow through the passage BI and into the part of chamber 38 that is located between the left piston head H and the adjacent end cap 60 to build up and to exert pressure on the left or closed end of the left piston head H. In the space between the right piston head '!I and the adjacent end cap 60 of the chamber 38, there is no controlling liquid pressure. As a result, the pressure against the end of the left piston head H compresses the spring 14 acting against said piston head while the other spring 74 operative against the-right pistonhead H is in its expanded 6 position, resulting in the position of the piston heads H shown in'Fig. 4, in which position the left head 11 of the reversing piston rests against the inner end of the left piston head H of the operating piston. As pressure builds up against the :left piston head 1|, the reversing piston is finally forced toward the right, and the roller 89 of the locking device is forced out of the right hand groove in the piston rod portion 18, thus releasing the left spring 14 andcausing-it to move the reversing piston toward theright until the roller 89 of the locking device engages in the left groove 80 of the piston rod portion 18. The discharge channel is now open by movement of the right piston head 11 away from it and the channel 40 is now closed by the left piston head 11. The fluid, now directed through the channel 4| will pass through the pipes 23 and 24, thus setting the upper left-hand spraying or rinsing head and the lower right-hand rinsing or spraying head in' operation, while the two other spraying :heads will then be rotated but will not spray. The time intervals for operating the'respective pairs of spraying or rinsing heads can be controlled by the throttling or needle valve 63 as will be readily apparent.

Due to leakage in the reversing valve above described, some slight variation in operating periods between the two pairs of spraying heads may occur, but this is not of consequence. By reason of such slight variation in operating periods of each pair of spraying heads, the particular position at which each spraying head reverses its direction of rotation tends to shift during operation of the apparatus.

The embodiment of the invention shown in Figs. 9 to 12 is of simpler construction than that just described, its primary difference being that a single piston i employed and the use of springs operative thereon has been eliminated. Move-'- ment of the piston is controlled through the pressure of the liquid and a successive opening and closing of the discharge channels is attained. In this embodiment of the invention, the valve housing m0 is attached to the bottom [5 of the casing or housing of the apparatus by means of the tubular or hollow screws IOI.

The valve housing IDS is shaped somewhat similarly to the housing 31 previously described, and includes a cylindrical chamber I62 in communication with a liquid-supply passage I83 and four discharge channels indicated respectively at I04, I05, H16 and H17. All of these channels extend laterally from the valve casing proper and substantially at right angles thereto and are in the form of bosses formed on and projecting from said housing I3 1). The two discharge channels I04 and I65 extend upwardly through the bottom l5 of the casing Ill and are connected with both of the upper rinsing or spraying devices I? by pipes or conduits arranged inside of the casing H). The two remaining discharge channels [06 and Hllextend horizontally and are connected by pipes or conduits on the outside of the casing. I!) to the lower rinsing or spraying heads. The supply channel N13 is directed downwardly and is connected to the liquid-supply pipe 26 as explained with respect to the first embodiment of the invention.

The chamber H32 in the valve housing I00 is closed at both of its ends by means of the threaded closure plugs I09. Each of said plugs is provided with a centrally located recess 0 from which extend radial passages III to thereby connect said central recess with an annular :throughrthe tubular rod 119, end :screws [23,

zlalticnshipabyza tubular rod El [9. .-Eormed infth'e iwall Ofithfl :tubular rod .119 3:13 an :aperture 12] which :ccmmum'cats with the interior T'O'f the tubular rod vtIjB and intheannular space beitweenithse inner-Wall surface of the ?rod and the tvalvermember generally indicated? at H1. .sAper- :ture -12! communication with the supply :passage 1.03, as will.beapparentirom-Fig; 9.

xThe valvemeans indicated generallysat H1 includes a solid rod I22 which extends axially washers 124 andqcoilsprings l 25 encircling the :rod .122 .at its opposite ends. The washers I24 azijdithezedgezoirthe'recess Hi! cfathe cover I09 a-form valve v1 head rand seat therefor, respectively.

In :Fig. 9 :the valve .118 shown in a position mhereinithezdis'charge:channels tfi-S and [01 are open. .At this time, the .ileft-han'd .valve .conzt-rolled' chann'el,consisting of the elements H0, IN, I I12, 1 land H4, isialso open since at this time the left valve-washer 124 is away from its -sfeat. It-will be-ncted thatxthe right-hand chan- Lneliis closed since the right washer .l24-is .mainitainedragainstziits seat and :thusv closes ,theright aperturellll. Liquid entering the supply-passage lll3willzpassthrough the aperture I21 and -1ficw through channel I20 to the chambers 10- ;cated'betweenthe outer: ends of thepistons H8 end-"the plugs H19. In-the left-hand chamber no .liquid pressure occurs since the liquid entering :therein will .be freely discharged by the'pvalve thereini-composed of the elements I26 and H9 being open. On-the right-hand side of Fig. 9 the-valve l24'-H0 is shut due to the liquid pressure acting to force the Washer 24 against the-inner end of theaperture I I B. As-this pres- ;sure builds up it 'willbe exerted against the right'endof the-piston head HG-andscon cause 4311618811116 120' be moved to the left. When-this :occurs, the left-piston head H16 willact to comipresstheileit spring I25 causing it tcfcrcethe rod l22 .andptheleftwasher l'241'thereon against the inn'erend of the aperture 1 l'ilwand; close said :aperture. Thi will bring the right washer I24 .away: from its-seat. Pressure will then begin to build-'upiinthe left chamber ,untilit is sufiicient .tQshif-tthe left piston to the right, jthereby relievingcsuch pressure and causing; a repetitions-of --t;he-rcycle above'describeid.

view-tot :the foregoing; it will nowzbev under "stood that the 'hydraulicallyioperated valve structure 25 in Figs. ,4 to 8 and similaravalve :structurein ,Figs. '9'-to 12,; act automatically to visuppiy liquid-yin a definite manner tc the rotatable spraying devices; I1. In-the operating :-posi -:tion ofvalvestructurelt as seenin- Figs. Aand 5,

sliquid isgbeing-supplied :to the top right-hand spraying: device I 1 and bottom deft-hand sprayinjg ;-',d8ViC8 ll in 'Fig. 2A. When the .operating piston .68 andrreversingzpistcn BB' in- Figs.:4 andi5 ashiitzto the irightxtor effectfclosingsofrchanneldll 1 and otnhannel- :A.t,r-zi-n'zthe"- manner prizviouslysexplainedp then liquid is supplied :ior an interval :of time to .the top deft-hand spraying device 1:1 and bottom right-handsnraying.device I! in 2A. :Inathi-samanner.sucwssive bodies of iliquidrdelivered through supp1y.-cQnd1lit:Z6 rare --alternately supplied to ianparticular paii'of spray.- ing devices I1, one of which is located-atthe top andxthewcthei rat the bottom :of the casing, or .ihousing 10.. In :addition, the spraying device it? which zarej active at any particular moment are iverticallyi'ofiset ifroin :oneyanother and ef.- Efective =.tc.. spray Iliquid :onto .different regions .of ;a batch of .dishes :being cleansed. "'Ishave discoveiedthatwhen the spraying devicesqfl :are :operatedjimthetinanner -just describedthemashing sneer is substantially zbetter'ithan:when. a11 .fourvspraying devices are :operated'rcontinuousqgly. This, mayberduetotthe faottthat ;the...1ine :pressure of the water supply :is :higherend :the :efiiciency of the apparatus is vincreased when only .two .rsp'raying .devices H are active at a particula-nmoment.

:In .Eig.;2.a-re shown the twcsspraying' devices H which are ;mounted'for.rotation about .dififerent-axesralcngside one anotheinat the zbottcm ;cf-.the casing HI. .In view of'the'manner in which :the valve structure .25 operates to supplyliquid :to the spraying devices, .at i any particular moment liquid supplied. under. pressure only to one of the spraying devices-in Fig. .2 Hence, when the left-hand spraying device H in :Fig. 2 is renderedoperable to spray liquid against dishes being cleansed, the right-hand sprayingdevice I1 is ,driven :by the .belt. connec- 130115.39 between the spraying devices. "While :the .left+hand;spraying.devioe1:1 is being hydrauli- .-cally driven, :therefore, --the right-hand spray.- .ing device is-rotating under what might be re.- .ferred to as a .fno-lcad condition. In other words, the right-hand spraying .device is not effective to spray 'liquidiand incapable of developing anyforce which will gimpart .rotating movement thereto. vHence,:the active left-hand spraying device actually constitutes :a .driving \member and the right-hand; spraying device the driven member for the conditions which .have .beenassumed; and in :such arrangement the right-hand spraying device ressentially acts as=a brake and "slows down the speedoi rotation of the left-handispraying device. "The; brakingaaction i rdue to the :friction cfjtherotata'ble mounting provisions :for. each spraying device'lwhen tit .is' being driven :by the other spraying rdevice whichis-active and to which liquid is beingsupplied. I-ihave discovered that the braking action "of the non-ractive spraying device? on the .-.active spraying deviceproduces several useful results Y in that" the force :atwhich-'the zindividualisliquid jets of *the active spraying device impinge wand strikethe 'dishes'being cleansed is increasedrand the 'field "of action of the individual 'jets is ;.im--

proved.

"In S'the -.embodlment of *Figs. "1 and. 2; an eat- 5 :ample, the grooves-'28 in the :arms 12] :act to change the direction. of the liquid I lets which issue ho'rizontally [from the jet heads 19,- and, after flowing "in the grooves, are deflected verticallyrupwar'd' in a;multiplicityxof difierent directions 'dependingupcn the angular extent of curvature of the individualgrooves. AS18661! in,Fig. 1, the. outer peripheral extremity of ;,certain grooves .eX-tend vertically upward a greater ;dis.. :tance; thaaotheneroor s, thus. producin s aced *1-5 rapantmeaisipoints :and val-levse-tnerebetweea The-vertically directedcomponent of force at which the deflected jets leave the grooves 28 in arms will is dependent on the difference between the angular velocity at which the jets issue from a nozzle head l9 and the angular velocity of the grooves 28 which in turn is dependent upon the angular velocity of the radially extending arms 21. When the diiference between the angular velocity of the jets issuing from a nozzle head l9 and angular velocity of the arms 2'! is relatively small, the vertical component of the force at which the deflected jets leave the grooves 28 is relatively small. However, when the difference between the angular velocity of the jets issuing from a nozzle head l9 and the angular velocity of the arms 2'! is relatively great, the vertical force component imparted to the deflected jets passing from the grooves 28 also will be relatively great. Hence, the breaking action of the driven sprayer on the active sprayer slows down the speed of rotation of the arms 27 of the latter, so that the difference in angular velocity between the jets issuing from a jet head [9 and arms 21 will be increased and thereby increase the vertical component of force imparted to the deflected jets leaving the grooves 28.

Also, since liquid is supplied intermittently to the different spraying devices I! by the operation of the valve structure 25, the spraying devices do notrotate continuously at a single constant speed but tend to decelerate at the moment the supply of liquid is being shifted and tend to accelerate after the shift is completed. Hence, the spraying heads [9 rotate at a speed which fluctuates, thereby causing variations in the difference between the angular velocity of the jets issuing from the jet heads l9 and angular velocity of the arms 21 which in turn results in variations in the vertical component of force imparted to the deflected jets passing from the grooves. This also results in producing jets which act in a greater number of directions and in effect increases the field of action of the jets.

This increase in the field of action of the jets, due to variations in speed of the spraying devices, perhaps may be brought out more clearly by explaining what happens when it is assumed the arms 21 remain stationary which will also be true of the grooves 28 formed in the arms.

'In such case the jets deflected by the grooves will issue from the latter in a direction coinciding with. theplane of the groove at its outlet end. Now, if the arms 2'! are allowed to turn and rotate, certain movement'will be imparted to the jets while being deflected during their issue in what may be referred to as an obliquely forward direction. 7

If the arms 21 rotated at a steady speed, the tangential component of movement imparted to the deflected jets would always be of the same component of force imparted to the jets being deflected in the grooves 28 will also vary, wherefore the extent to which the jets shift in an obliquely forward direction will always be shift- 10 ing; In this way the deflected jets will issue from the grooves in a great number of directions and be effective in a wide field of action.

In- Fig. 2 the spraying device H which is active rotates in a clockwise direction while the driven or inactive spraying device rotates in a counterclockwise direction by reason of the fact that the belt connection 30 therebetween is crossed. In the embodiment of Fig. 3, the left-hand spraying device 32 when active imparts clockwise movement to the arms 3| while the right-hand spraying device 32 when active imparts counterclockwise movement to the arms 3| associated therewith. Since the belt connection 30 in Fig. 3 is not crossed as in Fig. 2, each spraying'device 32 when inactive and driven by the other spraying device will rotate in the same direction as the spraying device acting as the driving member.

In both Figs. 2 and 3, however, a rapid deceleration of the active spraying device occurs when the supply of liquid thereto is cut off due to the braking action of the other-spraying device. In each embodiment the hydraulically operated valve structure begins to supply liquid to the liquid directing members 2! and 3!, respectively, of the spraying devices which are about to resume operation even before such spraying devices cease to be driven by the belt connections in a direction which is opposite to the direction that the hydraulically developed forces act to initiate turning movement of the spraying devices. With such an arrangement, liquid jets having a relatively great impact force issue from the spraying devices.

Having described several embodiments of the invention, it is obvious that the same-isnot .to be restricted thereto, but is broad enoughto. cover all structures within the scope of the-annexed claims.

What is claimed is: M, a

1. In dishwashing apparatus, a group of spaced apart spraying devices, means for mounte ing said spraying devices for rotatable movement about different axes, each ofsaid spraying devices being operable as a driving meansand active to spray liquid when. liquid ..is supplied thereto, connections includingcontrol means for supplying liquid to said sprayingdevices, means for mechanically coupling said rotatable spraying devices whereby, when onepart thereof in the group becomes active and operable as a driving means, said one part will impartmovement to another part in the groupv which is inactive and becomes a drivenmeans, mechanism operatively connected with said control means to cause the latter tosupplyliquid intermittently to each spraying device, said control means including said mechanism being constructed and arranged to render each spraying device active to spray liquid and becomes operable as a driving means for one interval of time andtorender each spraying device inactive to spray liquid and become a driven means for another interval of time, each movable spraying device i-n-the group, when inactive and becoming a drivenmeans-being effective to develop'a braking action on-the part of the group which-is operable as a driving means.

2. Apparatus asset forth in claim 1 in which the direction of movement of each spraying device and means for mechanically coupling said movable spraying devices are so inter-related that, when said control means including said mechanism becomes operable to. terminate the supply of liquid to -one spraying device and start the supply of liquid to anotherspraying device which up to -the moment has-been inacti-ve and a part of the driven-means; the-spraying device to which the supply or'liquid is being started will v offer maximum resistance to its: development as a driving means for-- the group (if-spraying devices.

3-. Apparatus as set forth in" claim 1-- in which said control means including said mechanism associated'therewithis soconstructed and arranged thatthe-supplyof'liquid to one spraying deviceywhichhas been inactive'and a part of the driven means, is started" while movement is still being-imparted thereto by anotheroi'the spraying devices which upto the moment has been astive-and' op erable as-a-driving-'means.'

4. Apparatus as set forth in claim I in-which said control means including said mechanism is constructed and'arranged to-termi'nate the supply" of liquid to one sprayingdevice and commence the supply of liquid to' another spraying device substantial-1yinstantaneously.-

5; Indishwashing apparatus; apair of spaced apart spraying devices, means for mounting said spraying devices for rotation about different axes, each of said spraying devices'becoming active. to spray liquid andembod'ying means operable to sheet positive rotation thereof responsive. to the pressure of the liquid supplied thereto, a supply line includingcontrol means for supplying? liquid, tosaid spraying'devicesysaid controlmeans embodying provisions tocause thezlat ter to' supply liquid alternatelyto'said spraying devices, each spraying device-alternately bein active to spray liquid and bepositively-rotated when liquidji's; being supplied thereto and ithen inactive to;spray liquid when-thesupply i' liquid thereto is cutoff: and means" connecting said rotatable spraying devices torender-each'spraw ing device when active operable to: drive;- and rotate the inactive spraying device 1 which then becomes'a' driven rotatable-means, each spraying device, when inactiveandbecomihg a driven rotatable means, being effectiveto' develop a braking action on the active spraying-device;

6; Dishwashing apparatus comprising a casing having a front access opening-and closure means therefor; two pairs of rotatable spraying devices of the kind specified in claim 5, one pair otsai'd' spraying devices being disposed at the vicinity of" the top of said casing and the other pair being disposed at the vicinity ofthe bottom oi said casing; the soraying-devices of each pair being offset laterally: with respect to one another. said control means beingso constructed and" arranged that the-sprayingdevices at-the top and bottom of'said cas n hich are active at a given moment arealways-offsetvertically from one another.

'7'; Dishwashing'apparatus asset-forth in claim 5 in which said rotatables raying devices are so' constructed and arranged that both rotate in thesame' d rection when liquid under pressure is-alternately supplied to the spraying devices, andsaid connecting'means being-so constructed and arranged that, when each rotatable sprayingdevice becomes activeand positively rotated in one direction when liquid is being supplied thereto, the other spraying device which is in.- active tov spray liquid is driven in theopposite direction from said active spraying device;

8. Dishwashing. apparatus asset forth in claim 5v n which said rotatable spraying devices are constructed and arranged that one device rotates inone direction and the other rotates in the opposite: directionwhen liquid: under press sure-- is alternately supplied' toz the: de vices, and: said connecting means being so constructed and arranged that, when: each-rotatable spraying? device becomes active-and positively rotated in one directionwhen liquid iszbeingsupplied thereto, the other spraying device which is inactive to spray liquid is driveninthe same direction as said active spraying device;

9: In dishwashing' apparatus, a casing having anaccess opening ina side wall thereof and closure means therefor; a first pair of, rotatable spraying devices at the-vicinity of the top-of said casing; a second pair of rotatable spraying devices at the vicinity ofthebottom ofsaid casing; eachof said rotatable-spraying devices becoming active to spray liquid and embodying means 0]): craole toe-fiect' positive rotation thereof respcm sive-tosupplyofliquid theretounder pressure; the spraying devices of each pair being laterally offset with respect to one another; a supplyline including hydraulically operated control means to supply liquidalternately to the spraying devices in each pair, each-sprayingdevice of a pair alternately being active to spray liquid and be positively rotated when liquid is'being' supplied thereto and then inactive to sprayliquid when the supply of'liquidthereto is cut off; and belt means connecting each pair of rotatable spraying devices at" the top and bottom, respectively-,- of said casing, each spraying device when inactlve becoming-a drivenrotatable means which is efiectiVetqpromote-a' brakingaction on: the active spraying device connected" thereto: by said beltmeans.

10;:Dishwashing-a;pparatus as set forth in claim .9' inwhich each spraying deviceat' the bottomor said casing isressentially beneath? one ofithetsprayingdevices'at the top; or saidcassaidihydraulically' operated control" means being-so; constructed; and arranged that the spraying ;.devices--atthe top" and bottom of said casing'which'are actiireat' a given moment are always" offset laterally-from' one another.

11. In dishwashingapparatus; a pairofspaced apartisprayingdevices; meansfor mounting said spraying devices forrotation aboutdifierent' axes. each of said spraying devices becoming active to spray. liquid andembodying means to effect-positive rotation thereof responsiveto supply of liquid thereto, under. pressure, a supply" line including hydraulically operatedcontrol structurefor sup plyingli'qui'd to. said'.'spraying devices, saidcontrol structure havi'nga. plurality oi outlet channels each of .Whichis in communication with one of saidspraying devices, said. control structure being. operable responsive toJiquid'under pressure to cause liquid to.be supplied alternately to said spraying devices,..each.sprayingdevice alternately being active to spray liquid and'be positively rotated when liquid isbeing supplied thereto .and then inactive, tospray liquid when the supply of liquid thereto is cut off, and" means connecting saidrotatable spraying devices to render each spraying device when active operable to drive and rotate the inactive spraying'device which then becomes a. driven .rotatable'means, each spraying device, when. inactive and. becoming a driven rotatablemeans, being. effective to. develop a brakingacti'on on the active sprayingdevice;

J OHAN FREDRIK ROBERT KARLSTROM;

(References on following page) REFERENCES CITED The following references are of record in the file of this patent:

UNITED- STATES PATENTS Number Name Date Rhodes Mar. 5, 1907 Gill Aug. 8, 1911 Schneider June 22, 1915 Merseles Nov. 3, 1925 10 Number Number Name Date Ferris July 13, 1926 Johnston Nov. 6, 1934 George Mar. 16, 1937 Dunham Jan. 5, 1943 Hertz Mar. 27, 1945 FOREIGN PATENTS Country Date Germany Nov. 1, 1935

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