Patent Publication Number: US-7896977-B2

Title: Dishwasher with sequencing corner nozzles

Description:
BACKGROUND OF THE INVENTION 
     Contemporary dishwashers include a tub and an upper and lower rack or basket for supporting soiled utensils within the tub. A pump is provided for re-circulating wash liquid throughout the tub to remove soils from the utensils. The pump normally recirculates the liquid through a rotating spray arm located beneath a rack. One of the problems associated with contemporary dishwashers is that the utensils do not receive uniform wash treatment depending upon their positioning within a rack in the dishwasher. For example, in a typical dishwasher, the racks have a square planform and the rotating spray arms define a circular plane, which does not extend to the corners of the rack, providing the corners of the rack with a lesser wash performance. 
     SUMMARY OF THE INVENTION 
     The invention relates to an automatic dishwasher with a wash chamber for receiving utensils to be washed. The wash chamber also houses at least one spray nozzle to spray liquid inside the chamber, a valve selectively operable to fluidly couple the at least one spray nozzle to a liquid supply and a rotating spray arm for introducing liquid into the wash chamber and operably coupled to the valve such that rotation of the spay arm selectively operates the valve to fluidly couple the at least one spray nozzle to the liquid supply. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic view of a dishwasher according to the invention with wash chamber, upper and lower utensil racks, corner spray nozzles, and a valve. 
         FIG. 2  is a top view of a second embodiment of the invention showing the upper utensil rack, upper rotating spray arm, corner spray nozzles, and valve. 
         FIG. 2A  is similar to  FIG. 2  except that the rack has been removed to better see the spray arm, spray nozzles, and valve. 
         FIG. 3  is an exploded view of the valve of  FIGS. 2 and 2A . 
         FIG. 4  is a first cut away view of the upper utensil rack of  FIG. 2 . 
         FIG. 5  is a second cut away view of the upper utensil rack of  FIG. 2 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     Referring now to  FIG. 1  an embodiment of the invention is illustrated comprising an automated dishwasher  10  having a housing  12 . The dishwasher  10  shares many features of a conventional automated dishwasher, which will not be described in detail herein except as necessary for a complete understanding of the invention. The housing  12  has spaced top and bottom walls  16  and  18 , and spaced sidewalls  20 . The walls  16 ,  18 , and  20  join along their respective edges to define a wash chamber  24 . As one of skill in the art will appreciate, the front wall may be the door of the dishwasher  10 , which may be pivotally attached to the dishwasher  10  for providing accessibility to the wash chamber  24  for loading and unloading utensils or other washable items. While the present invention is described in terms of a conventional dishwashing unit as illustrated in  FIG. 1 , it could also be implemented in other types of dishwashing units such as in-sink dishwashers or drawer dishwashers. 
     Utensil holders in the form of upper and lower utensil racks  15 ,  17  are located within the wash chamber  24  and receive utensils for washing. The upper and lower racks  15 ,  17  are typically mounted for slidable movement in and out of the wash chamber  24  for ease of loading and unloading. As used in this description, the term utensil is generic to dishes and the like that are washed in the dishwasher  10  and expressly includes, dishes, plates, bowls, silverware, glassware, stemware, pots, pans, and the like. 
     The bottom wall  18  of the dishwasher may be sloped to define a lower tub region or sump  30  of the tub. A pump assembly  31  may be located in or around a portion of the bottom wall  18  and in fluid communication with the sump  30  to draw wash liquid from the sump  30  and to pump the liquid to at least a rotating lower spray arm assembly  32 . If the dishwasher has a rotating mid-level spray arm assembly  33  and/or an upper spray arm assembly  34 , liquid may be simultaneously or selectively pumped through a supply tube  35  to each of the assemblies for selective washing. 
     In this embodiment, the rotating lower spray arm assembly  32  is positioned beneath a lower utensil rack  15 , the rotating mid-level spray arm assembly  33  is positioned between an upper utensil rack  17  and the lower utensil rack  15 , and the upper spray arm assembly  34  is positioned above the upper utensil rack  17 . The rotating lower spray arm assembly  32  is configured to rotate in the tub and spray a flow of wash liquid from at least one outlet  40 , in a generally upward direction, over a portion of the interior of the tub. The spray from the rotating lower spray arm assembly  32  is typically directed to wash utensils located in the lower utensil rack  15 . Like the rotating lower spray arm assembly  32 , the rotating mid-level spray arm assembly  33  may also be configured to rotate in the dishwasher  10  and spray a flow of wash liquid from at least one outlet  40 , in a generally upward direction, over a portion of the interior of the tub. In this case, the spray from the rotating mid-level spray arm assembly  33  is directed to utensils in the upper utensil rack  17 . In contrast, the upper spray arm assembly  34  generally directs a spray of wash liquid in a generally downward direction and helps wash utensils on both upper and lower utensil racks  15 ,  17 . The wash liquid may be water, a wash aid or any combination there of. Examples of common wash aids include: a detergent, a spot reducer, a rinse agent, a stain remover, bleach, or any other similar product that facilitates excellent cleaning of the utensils. 
     The pump assembly  31 , spray arm assemblies  32 - 34  and supply tube  35  collectively form a liquid recirculation system for spraying wash liquid within the wash chamber  24 . The pump draws liquid from the sump  30  and delivers it to one or more of the spray arm assemblies  32 - 34  through the supply tube  35 , where the liquid is sprayed back into the wash chamber  24  through the spray arm assemblies  32 - 34  and drains back to the sump  30  where the process is repeated. 
     A heater  36  is located within the sump for heating the wash liquid contained in the sump. A controller  50  is operably coupled to the pump assembly  31  and heater  36  and controls the operation of the pump assembly  31  and heater  36  to implement the selected cycle. The controller  50  may comprise a user interface enabling the user to select the desired wash cycle and set correspondingly relevant parameters or options for the cycle. A control panel  51 , shown in phantom, may be coupled to the controller  50  and may provide for input/output to/from the controller  50 . The control panel may be any suitable input/output device, such as a touch panel, switches, knobs, displays, indicators, etc., and any combination thereof. 
     Referring now to  FIGS. 2 and 2A , a spray nozzle  60  is located in a first corner of the upper utensil rack  17 , a second spray nozzle  61  is located in a second corner of the upper utensil rack  17 , a third spray nozzle  62  is located in a third corner of the upper utensil rack  17 , and a fourth spray nozzle  63  is located in a fourth corner of the upper utensil rack  17 . Each spray nozzle  60 - 63  may be fixed to the upper utensil rack  17  and configured to provide a second flow of wash liquid over a portion, or several portions, of the interior of the wash chamber  24 . This additional liquid may create a separate wash zone or an intensified wash zone in the wash chamber  24 . Each spray nozzle  60 - 63  may be mounted in any configuration on the upper utensil rack  17 . For that matter, the invention contemplates that spray nozzles may be mounted anywhere upon the interior of the wash chamber or on the lower utensil rack  15 . 
     Referring to  FIG. 2A , a valve assembly  70  is fluidly coupled to the rotating mid-level spray arm assembly  33  and to the spray nozzles  60 - 63  to selectively supply fluid to the spray nozzles  60 - 63 . Multiple conduits  65  extend from the valve assembly  70  to a corresponding one of the spray nozzles  60 - 63  to establish a fluid connection between the valve assembly  70  and the spray nozzles  60 - 63 . The valve assembly is fluidly coupled to the interior of the rotating mid-level spray arm assembly  33 . With the configuration, the valve assembly  70  can draw fluid supplied to the interior of the spray arm from the pump  31  and direct it to the spray nozzles  60 - 63 . The supply of fluid from the spray arm to the spray nozzles  60 - 63  can be done simultaneously or sequentially. It is anticipated that it will be done consecutively to ensure fluid with sufficient pressure for cleaning is sprayed from the nozzles  60 - 63 . 
       FIG. 3  is an exploded view of the parts making up the valve assembly  70 . The parts can be arranged in three functional groupings: a lower mount  71 , a drive assembly  80 , and a water distribution unit  90 . The lower mount  71  functions to attach the valve assembly  70  to the lower surface of the upper dish rack  17  and to fluidly couple the valve assembly  70  to the supply tube  35 . The water distribution unit  90  operates as a manifold to distribute water coming from the supply tube  35 , through the lower mount  71 , to the multiple conduits  65 . The drive assembly  80  drives the water distribution unit  90 . 
     Looking at each of the functional groups in greater detail, the lower mount  71  couples to the wires forming part of the lower surface of the upper dish rack  17 . The lower mount  71  has a C-shaped holder  73  and a U-shaped holder  74  that secure the valve assembly  70  to the upper dish rack  17 . The C-shaped holder  73  is normally slid onto a wire  73 A of the rack. The lower mount  71  is then rotated about the interface of the C-shaped holder  73  and the corresponding wire to bring the U-shaped holder into contact with the corresponding wire  74 A and snap beneath spring finger  75 . The lower mount  71  has a base  76  that supports the bottom of the drive assembly  80  when the valve assembly is fully assembled. The lower mount  71  has a single inlet  72 , which fluidly couples the valve assembly  70  to the supply tube  35 . Drive shaft opening  77  extends through the lower mount  71 . Fluid passages  79  are spaced about the periphery of the lower mount  71  and are fluidly coupled to the single inlet  72  to effect the transfer of fluid through the lower mount  71  from the inlet  72 . 
     The drive assembly  80  is composed of a gear box  82 , a first drive shaft  83 , a second drive shaft  84 , a first gear  85 , a carrier  86 , a second gear  87 , an output gear  88 , and a gear plate  89  that all combine to form an epicyclical gear drive. The gear box  82  has a seven-sided interior recess  82 A that houses a gear stack formed by the gears  85  and  87 , gear chain  86 , and output shaft  88 . Multiple fluid passages  82 B, complementary to fluid passages  79 , extend through the gear box  82  and are located exteriorly of the recess  82 . 
     Looking at the gear stack in more detail, the first gear  85  has six sides and is operably coupled to the underside of the carrier  86  through pins  85 A. The carrier  86  also has a projection  86 A. The projection  86 A is set off center of the rotational axis of the drive shaft  84  and as the projection  86 A rotates it defines an orbital path around the rotational axis of the drive shaft  84 . The carrier  86  is operably coupled to the second gear  87  by the projection  86 A being received within the opening  87 B such that the second gear  87  tracks the orbital path made by the projection  86 A. The second gear  87  also has six teeth and is operably coupled to the output gear  88  by pins  87 A being received within openings  88 A. The output gear  88  has an output shaft  88 B for coupling to the water distribution unit  90 . 
     The gear assembly has a 36:1 gear reduction such that a 22 to 24 rpm of the rotating mid-level spray arm assembly  33  results in a thirty-second spray time per each corner nozzle. Although the gear assembly shown is an epicyclical gear assembly; it has been contemplated that other types of gear assemblies could be used. 
     A seal plate  89  abuts the gear box  82  such that it closes the top of the recess  82  and seals the recess  82  and the gears inside relative to the fluid passages  82 B. The seal plate  89  has a central opening  89 A for passage of the output shaft  88 B and openings  89 B that are complementary to fluid passages  82 B. The openings  89 B further continue the fluid path from the supply tube  35  through the lower mount  71  and the gear box  82 . 
     The first drive shaft  83  is received within the lower mount  71  such that it is free to rotate. It has an upper portion  83 A that extends into the drive shaft opening  77  of the lower mount  71 . It also has a lower portion  83 B that forms a mount and is coupled to the spray arm  33  such that rotation of the spray arm  33  will rotate the first drive shaft  83 . The lower portion  83 B is configured such that it snaps into the rotating mid-level spray arm assembly  33  to effect the coupling therebetween. The second drive shaft  84  is inserted into an axial opening  83 D in the upper portion  83 A and is operably coupled to the underside of the first gear  85  by a catch  84 A. In this way, the rotation of the spray arm results also rotates the drive shafts  83 ,  84 , which in turn rotate the output shaft  88 B via the gear stack at the selected reduction ratio. 
     The water distribution unit  90  comprises a diverter disk  91  and an upper housing  92  with four outlets  93 ,  94 ,  95 , and  96 . The upper housing  92  further comprises four separate sections each fluidly connected to one of the four outlets  93 - 96 . Each of the four outlets  93 - 96  is fluidly coupled to a separate spray nozzle  60 - 63  by multiple conduits  65 . The diverter disk  91  has a single hole  91 A through which water may flow from the lower mount  71  and gear box  82  into one of the four separate sections of the upper housing  92 . The output shaft  88 , of the drive assembly  80 , is operably coupled to the diverter disk  91  and operates to rotate the diverter disk  91  as the rotating mid-level spray arm assembly  33  rotates. Movement of the diverter disk  91  allows fluid coupling between wash liquid in the lower mount  71  and gear box  82  to each of the four individual sections of the upper housing  92  consecutively. Thus, the water distribution unit  90  allows for sequential fluid coupling of water in the lower mount  71  to each of the spray nozzles  60 - 63 . 
     Referring to  FIG. 4 , when the valve assembly  70  is assembled, it provides for fluid paths, as shown by the arrows, from the supply tube  35  to the water distribution unit  90 . The flow paths are formed by the complementary fluid passages  79  in the lower mount, passages  82 B in the gear box  82 , and openings  89 A in the seal plate. These fluid paths extend from the supply tub  35  to a chamber  97  in the distribution unit  90  defined by the space between the diverter disk  91  and the seal plate  89 . The opening  91 A fluidly connects the chamber  97  to the corresponding outlet  93 ,  94 ,  95 , and  96 . 
       FIG. 4  also illustrates the connection of the drive assembly. The second drive shaft  84  is shown with its lower portion received within the axial opening  83 D of the lower drive shaft and its upper portion extending through the gear stack and terminating in the lower portion of the portion output gear  88 . In this way, the upper portion of the second drive shaft  84  aids in aligning all of the parts of the gear stack. The pins  85 A are shown received in recesses in the carrier  86 , which are similar to the openings  88 A in the output gear  88 . The lower portion  83 B of the first drive shaft  83  is shown coupled to the rotating spray arm  33 , which resides below the inlet  72 . With this configuration, the rotation of the spray arm  33  effects the rotation of the diverter disk  91 . 
     During operation of the dishwasher  10 , the valve assembly  70  may be employed to control the volume of the stream of liquid from the rotating mid-level spray arm assembly  33  to each of the spray nozzles  60 - 63 . When time comes to spray wash liquid into the wash chamber  24  the controller  50  signals the pump assembly  31  to supply wash liquid to the spray arm assemblies  32 - 34  through the supply tube  35 . When the wash liquid reaches the lower mount  71  a large portion goes to the rotating mid-level spray arm assembly  33 . The wash liquid sprayed from the rotating mid-level spray arm assembly  33  causes it to rotate. The rotation turns the first drive shaft  83 , which in turn causes the gear assembly to move and for the diverter disk  91  to slowly turn. Movement of the diverter disk  91  rotates the opening  91 A to sequentially bring it into fluid coupling with a different section of the housing  90  corresponding to each of the outlets  93 - 96 . The amount of time that the opening  91 A is in fluid coupling with each of the outlets  93 - 96  controls the duration of the time that each nozzle  60 - 63  sprays liquid. The time of fluid coupling can be thought of as a dwell time. With the described valve assembly configuration, the dwell time can be controlled by the gear reduction ratio and the flow rate of water. 
     It should be noted that the supply tube  35  feeds water to both the rotating mid-level spray arm assembly  33  and the valve assembly  70 . Thus, the valve assembly  70  is actually diverting a small amount of the water intended for the rotating mid-level spray arm assembly  33 . The valve assembly  70  only diverts a portion of the wash liquid from the rotating mid-level spray arm assembly  33  because if too much wash liquid is diverted the rotating mid-level spray arm assembly  33  will stop rotating. For the illustrated configuration, the liquid flow rate sufficient to cause the spray arm to rotate at a steady rate and overcome the inherent resistance of the valve assembly is a flow rate that results in a rotational rate of the spray arm of at least around 17 rpm. 
     Further, it has been contemplated that the invention may differ from the configuration shown in  FIGS. 1-5 , such as by inclusion of other conduits, utensil racks, valves, spray nozzles, and the like, to control the flow of the stream of wash liquid. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.