Patent Application
20090159103
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.
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.
In the drawings:
Referring now to
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
Referring to
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 73A 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 74A 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 82A that houses a gear stack formed by the gears 85 and 87, gear chain 86, and output shaft 88. Multiple fluid passages 82B, 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 85A. The carrier 86 also has a projection 86A. The projection 86A is set off center of the rotational axis of the drive shaft 84 and as the projection 86A 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 86A being received within the opening 87B such that the second gear 87 tracks the orbital path made by the projection 86A. The second gear 87 also has six teeth and is operably coupled to the output gear 88 by pins 87A being received within openings 88A. The output gear 88 has an output shaft 88B 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 82B. The seal plate 89 has a central opening 89A for passage of the output shaft 88B and openings 89B that are complementary to fluid passages 82B. The openings 89B 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 83A that extends into the drive shaft opening 77 of the lower mount 71. It also has a lower portion 83B 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 83B 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 83D in the upper portion 83A and is operably coupled to the underside of the first gear 85 by a catch 84A. In this way, the rotation of the spray arm results also rotates the drive shafts 83, 84, which in turn rotate the output shaft 88B 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 91A 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
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 91A 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 91A 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
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.
