Patent Publication Number: US-2017354307-A1

Title: Improved rotating spray arm and dishwasher having the same

Description:
The present invention relates to a dishwasher, in particular a domestic dishwasher. The present invention more particularly relates to the rotating spray arms of the dishwasher. 
     Domestic dishwashers are commonly known. A domestic dishwasher generally comprises a tub, an upper pull-out rack, a lower pull-out rack, an upper rotating spray arm and a lower rotating spray arm which are associated with the upper pull-out rack and the lower pull-out rack respectively, a sump which is arranged into the bottom of the tub for collecting the wash liquor, a heater for heating the wash liquor, and a pump for supplying the rotating spray arms with pressurized wash liquor. The rotating spray arm generally comprises a main body, an inlet port for receiving the supplied wash liquor, a channel inside the main body for conducting the wash liquor, an outlet port for discharging the wash liquor, wherein the inlet port and the outlet port open both into the channel, and a mounting means for rotatably and releasably mounting the main body into the tub. During the course of washing, the rotating spray arms sprinkle the articles inside the racks with wash liquor through their nozzles in the outlet port. The wash liquor resolves the dirt from the articles and drains down together with the resolved dirt onto the bottom of the tub. To avoid recirculation of the dirt through the pump into the rotating spray arms, a filter apparatus is generally arranged into the bottom of the tub and upstream of the sump. The filter apparatuses which are used in domestic dishwashers are commonly known. The filter apparatus generally comprises a fine filter which has a filter surface and an aperture into which a releasable filter assembly has been inserted. The filter assembly has a coarse filter which is embedded into a micro filter for sequentially filtering the dirt and draining the wash liquor into the sump. The filter surface is usually inclined downwards towards the center of the filter assembly and has a plurality of fine ports for filtering the dirt and draining the wash liquor into the sump. The filter assembly comprises a plurality of openings for admitting the wash liquor which streams downwards along the filter surface into the coarse filter and the micro filter. 
     In general, the filter apparatus must be regularly cleaned to prevent it from clogging. In the event of clogging, the dirt which is trapped by the filter apparatus is disintegrated through the suction effect of the pump, and subsequently infiltrated. Thus, the turbidity of the circulating wash liquor increases and the cleaning performance decreases. In the event of clogging, also the dirt in the circulating wash liquor starts to soil and clog up the rotating spray arms. Even when the filter apparatus is subsequently cleaned by the user, the cleaning performance may still remain degraded due to the dirty or eventually clogged rotating spray arms. In such cases, the user contacts the customer service and complains about the poor cleaning performance. In general, the maintenance of the rotating spray arms are comparatively cost-intensive since it generally requires the replacement of the dirty and clogged rotating spray arms through a service person. 
     An objective of the present invention is to provide a rotating spray arm for use in a dishwasher, and a dishwasher having the same which overcomes the aforementioned drawbacks of the prior art in a cost effective way and which enables an improved cleanliness and an improved cleaning performance. 
     This objective has been achieved by the rotating spray arm as defined in claim  1 , and the dishwasher as defined in claim  14 . Further achievements have been attained by the subject-matters respectively defined in the dependent claims. 
     The rotating spray arm of the present invention comprises one or more than one openable/closable aperture for manually flushing out its channel and ports with tap water or detergent containing water. The rotating spray arm of the present invention also comprises an opening/closing means for manually and leak-tightly opening/closing each aperture. Each aperture opens into the channel and is fluidly connected with the inlet port and outlet port. 
     With the present invention, the user has been enabled to flush out the dirt and soil inside the rotating spray arms in the event of clogging. The user may, of course, clean the rotating spray arms also regularly for improving the cleanliness of the dishwasher even before the occurrence of any clogging. With the present invention, the user has been enabled to clean the interior of the rotating spray arms by way of demounting the spray from the tub, opening the aperture of the rotating spray arm, and flushing out the channel and the ports with tap water or detergent containing water through the aperture. After the flushing process, the user closes the aperture and remounts the rotating spray arm into the tub. Thereby, the cleaning performance of the dishwasher can be easily recovered. With the present invention, the need for replacing the clogged rotating spray arm by a new one through a service person has been obviated or reduced as much as possible. In addition, the cost for the replacement through the customer service as well as the valuable resources can be saved. With the present invention, the cleanliness and the cleaning performance of the dishwasher have been improved. Thereby, the customer satisfaction can be increased. 
     In an embodiment, the opening/closing means comprises a closure member such as a closure cap or a closure lid which can be leak tightly attached to the corresponding aperture by hand. In this embodiment, the closure member is releasable. Alternatively the closure member can be hinged on the rotating spray arm through an integral or a separate hinge. In this embodiment, the attachment between the closure member and the aperture is established by a bayonet connection, a threaded connection, a snap-fit connection, a press fit connection or the like. 
     In another embodiment, a gasket is disposed between the closure member and the aperture for improving the leak-tightness. 
     In another embodiment, the aperture is located in close proximity to the tips of the rotating spray arm. In this embodiment, only one of the tips has an aperture. Alternatively both of the tips may be provided with a separate aperture. The aperture may have a diameter which ranges between one to four centimeters. 
     In another embodiment, the aperture has a relatively large size in comparison with the size of the nozzles of the outlet port such that any pieces of dirt can be easily removed through the aperture to the outside. 
    
    
     
       Additional advantages of the rotating spray arm and the dishwasher of the present invention will become apparent with the detailed description of the embodiments with reference to the accompanying drawings in which: 
         FIG. 1 —is a schematic perspective view of a dishwasher which has rotating spray arms according to an embodiment of the present invention; 
         FIG. 2 —is a schematic perspective view of a rotating spray arm according to an embodiment of the present invention, prior to closing the aperture with a closure cap; 
         FIG. 3 —is another schematic perspective view of the rotating spray arm according to an embodiment of the present invention, prior to closing the aperture with the closure cap; 
         FIG. 4 —is a schematic enlarged partial perspective view of the rotating spray arm according to an embodiment of the present invention, prior to closing the aperture with the closure cap; 
         FIG. 5 —is a schematic enlarged partial perspective view of the rotating spray arm according to an embodiment of the present invention, prior to rotating the closure cap from the unlocked state to the locked state; 
         FIG. 6 —is a schematic enlarged partial perspective view of the rotating spray arm according to an embodiment of the present invention, after having rotated the closure cap to the locked state; 
         FIG. 7 —is a schematic enlarged perspective view of the closure cap according to an embodiment of the present invention. 
     
    
    
     The reference signs appearing on the drawings relate to the following technical features. 
       1 . Rotating spray arm 
       2 . Dishwasher 
       3 . Main body 
       4 . Inlet port 
       5 . Channel 
       6 . Outlet port 
       7 . Mounting means 
       8 . Aperture 
       9 . Opening/closing means 
       10 . Closure cap 
       11 . Connector 
       12 . Connector 
       13 . Projection 
       14 . Recess 
       15 . Flange 
       16 . Plug 
       17 . Grip 
       18 . Hub 
     The rotating spray arm ( 1 ) is suitable for use in a dishwasher ( 2 ). 
     The rotating spray arm ( 1 ) comprises a main body ( 3 ), an inlet port ( 4 ) for receiving wash liquor, a channel ( 5 ) inside the main body ( 3 ) for conducting the wash liquor, an outlet port ( 6 ) for discharging the wash liquor, wherein the inlet port ( 4 ) and the outlet port ( 6 ) open both into the channel ( 5 ) and a mounting means ( 7 ) for rotatably and releasably mounting the main body ( 3 ) into the tub (not shown) of the dishwasher ( 2 ). 
     The rotating spray arm ( 1 ) of the present invention comprises an openable/closable aperture ( 8 ) for flushing out the channel ( 5 ) and said ports ( 4 , 6 ) with tap water or detergent containing water, wherein the aperture ( 8 ) opens into the channel ( 5 ) and an opening/closing means ( 9 ) for manually and leak-tightly opening/closing the aperture ( 8 ). 
     The dishwasher ( 2 ) of the present invention comprises a tub, and one or more than one rotating spray arm ( 1 ) which is rotatably mounted into the tub. 
     In an embodiment, the opening/closing means ( 9 ) comprises a releasable closure cap ( 10 ) for manually and leak-tightly opening/closing the aperture ( 8 ). In this embodiment, the closure cap ( 10 ) has a bayonet connector ( 11 ). And the aperture ( 8 ) has a counterpart bayonet connector ( 12 ) which locks with or unlocks from the bayonet connector ( 11 ) upon rotation. 
     In another embodiment, the bayonet connector ( 11 ) comprises two diametrically opposed projections ( 13 ) which are disposed on the closure cap ( 10 ). And the counterpart bayonet connector ( 12 ) has two diametrically opposed matching recesses ( 14 ) which are disposed in the periphery of the aperture ( 8 ). The projections ( 13 ) respectively fit through the recesses ( 14 ) in the unlocked state, and the catch from below the periphery of the aperture ( 8 ) in the locked state. 
     In alternative embodiments, the closure cap ( 10 ) and the aperture ( 8 ) are releasably connectable respectively via a threaded connection, a snap-fit connection or a press fit connection instead of the above-described bayonet connection. 
     In another embodiment, the closure cap ( 10 ) has a flange ( 15 ) for seating onto the periphery of the aperture ( 8 ). In this embodiment the closure cap ( 10 ) also has a plug ( 16 ) for fitting into the aperture ( 8 ). In this embodiment, the projections ( 13 ) are disposed onto the underside of the plug ( 16 ). 
     In another embodiment, the closure cap ( 10 ) has a grip ( 17 ) for holding with the fingers. 
     In another embodiment, the grip ( 17 ) has a semicircular shape. 
     In another embodiment, that the closure cap ( 10 ) is moulded as a single piece from plastic material ( FIG. 1 to 7 ). Alternatively the closure cap ( 10 ) can be manufactured from metal. 
     In another embodiment, the rotating spray arm ( 1 ) has a gasket (not shown) which is disposed between the closure cap ( 10 ) and the periphery of the aperture ( 8 ). 
     In another embodiment, the aperture ( 8 ) is disposed in close proximity to the tip of the main body ( 3 ). 
     In another embodiment, the main body ( 3 ) has an upper side and a lower side. In this embodiment, the inlet port ( 4 ) and the aperture ( 8 ) are disposed onto the upper side. 
     In another embodiment, the main body ( 3 ) has a hub ( 18 ). In this embodiment, the mounting means ( 7 ) and the inlet port ( 4 ) are disposed onto the hub ( 18 ). 
     In another embodiment, the main body ( 3 ) extends in diametrically opposed radial directions with respect to the rotation axis of hub ( 18 ). 
     In another embodiment, the outlet port ( 6 ) has one or more than one nozzles (not shown). 
     With the present invention, the user has been enabled to flush out the dirt and soil inside the rotating spray arms ( 1 ) through the openable/closable aperture ( 8 ). Thereby, the user can easily increase the cleanliness and recover the cleaning performance of the dishwasher ( 2 ) in the event of clogging. With the present invention, the customer satisfaction can be increased.