Patent Publication Number: US-2010116301-A1

Title: Top spray device for dishwashers

Description:
The invention relates to a dishwasher, in particular a domestic dishwasher in accordance with the preamble of claim  1 . 
     A dishwasher is known from EP 1 382 287 A2, which has a top spray device which can be supplied with washing solution by way of the line system in the dishwasher. In this situation, the top spray device is arranged centrally in the center of the top of the washing compartment. The top spray device has a rotatably mounted spray head which is attached to a water conduit by means of a clip. The water line has an opening, through which the spray head can be supplied with spray solution, which then exits through a plurality of spray openings in the spray head and in doing so causes the spray head to rotate such that an even distribution of the washing solution over the items to be cleaned is ensured. There is however a danger of soilings accumulating in the area of the rotatable mounting of the spray head, in particular in the area of the connecting pieces encroaching into the spray head, such that the reliable operation of the top spray system is not guaranteed. 
     The object of the invention is therefore to provide a remedy here. 
     The object of the invention is achieved by a dishwasher, in particular a domestic dishwasher, comprising a hydraulic system and at least one top spray device arranged above at least one basket for items to be washed, in particular a basket for items to be washed taking the form of a cutlery drawer, which can be supplied with washing solution by means of the hydraulic system, and which has a rotatable spray head which is attached to the hydraulic system by means of a cage, characterized in that the spray head can be supplied with washing solution by way of a free path. As a result of supplying the spray head by way of a free path, it is possible to considerably increase the reliability of the top spray device because it thus becomes possible to dispense with a shaft connection between spray head and hydraulic system, in the area of which soilings can easily accumulate. In addition, the construction and the assembly are simplified because there is no longer a requirement for a water-bearing shaft connection between rotatable spray head and hydraulic system. 
     Provision is preferably made such that the spray head is rotatably mounted in the cage, in other words there is no shaft connection between spray head and lines belonging to the hydraulic system. This enables the rotatable mounting of the spray head to be arranged in an area in which only a low level of soiling by washing solution is to be reckoned with, for example an area on the underside of the rotatable spray head, in other words on the side which faces away from the top of the washing compartment and faces the base of the washing compartment. 
     Provision is preferably made such that the cage has a shaft journal engaging in a seat in the spray head. It is however also possible for the spray head to have a shaft journal which engages in a seat in the cage. 
     Provision is preferably made such that the spray head has a central deflector surface. The central deflector surface forms the end of the free path which is arranged with an outlet at an end section of a line belonging to the hydraulic system. The spray head has a turbine wheel shaped design, wherein a plurality of guide elements form a plurality of channels, through which washing solution can be evenly distributed during operation onto items including cutlery to be washed to act thereon. 
     In this situation, provision is preferably made such that the central deflector surface is implemented in order to direct washing solution into the channels so as to ensure that the washing solution is directed essentially loss-free from the free path by way of the central deflector surface into the channels and finally to the items including cutlery to be washed to act thereon. 
     To this end, the central deflector surface can exhibit any desired suitable form. Provision is preferably made such that the central deflector surface is implemented to be essentially conical in shape. This allows a particularly advantageous implementation of the spray head to be realized, wherein the conically implemented central deflector surface is arranged with its apex in the direction of the top of the spray compartment, whereby in the interior of the conically implemented deflector surface a seat for a shaft journal is formed in the cage, in other words such that the seat is arranged opening in the direction of the base of the washing compartment. 
     In addition, provision is preferably made such that the spray head is implemented to be essentially rotationally symmetrical, in other words it essentially has a turbine wheel like shape with an essentially constant diameter and radius. This permits a compact type of construction and problem-free incorporation in a cage likewise implemented to be essentially rotationally symmetrical. 
     Furthermore, provision is preferably made such that the cage is attached to the hydraulic system by means of a snap-action connection. To this end, at two sides situated opposite one another the cage has two elastically deflectable snap-action elements which in the mounted state engage in corresponding recesses in the end section of a line belonging to the hydraulic system, such that problem-free assembly and where applicable disassembly is possible in order to be able to carry out cleaning work when required. 
     In addition, a top spray device for incorporation in a dishwasher and also a spray head and a cage for forming a spray device of this type belong to the invention. 
    
    
     
       The invention will be described in the following with reference to a drawing. In the drawings: 
         FIG. 1 : shows a schematic representation of a top spray device according to the invention on a line, 
         FIG. 2 : shows an exploded view of a top spray device according to the invention with a line section, and 
         FIG. 3 : shows a top view of a schematic representation of a spray head according to the invention. 
     
    
    
     Illustrated is a line  20 , belonging to the hydraulic system  2  of the dishwasher, which can be implemented to have a plurality of channels on a single level and, through a connection with the circulating pump, serves to supply the spray arms for applying washing solution to the items to be washed. 
     A top spray device  4  is arranged on an end section  22  of the line  20 . In this situation, the line  20  is dimensioned such that the end section  22  with the top spray device  4  is arranged centrally in the top area of the washing compartment and can be used for example to evenly apply washing solution to a basket for items to be washed implemented as a cutlery drawer. 
     The top spray device comprises a rotatable spray head  6  and a retaining element implemented as a cage  8 . Both the spray head  6  and also the cage  8  are manufactured from a plastic material which is selected in accordance with the conditions in the interior of a dishwasher, in other words which in particular is appropriately resistant to temperature and chemicals. 
     The rotatable spray head  6  has a turbine wheel like shape and is therefore implemented to be essentially rotationally symmetrical with an essentially constant diameter and radius. The upper side  30  of the spray head  6  has a plurality of guide elements  18  which form channels, running radially outwards. Centrally in the center of the spray head  6  is arranged a deflector surface  14  which is implemented to rise conically from the upper side  30  such that washing solution striking the central deflector surface  14  is guided by the conical shape in conjunction with the guide elements  18  through the channels  16  to the edge of the spray head  6 . In addition, two cutouts  34  are provided, by means of which washing solution can be deflected not in the radial direction but can pass directly downwards, in other words in the direction of the base of the washing compartment, with the result that areas arranged directly beneath the spray head  6  are also supplied with washing solution. 
     The underside  32  of the spray head  6  has a seat which extends into the interior of the conically configured deflector surface from beneath and is implemented to accommodate a shaft journal  12  belonging to the cage  8 . 
     The cage  8  has an essentially likewise rotationally symmetrical shape with constant radius and diameter; the cage  8  comprises a grid structure  28  which has in a central position the shaft journal  12  which engages in the seat in the spray head  6 . In order to attach the cage ( 8 ), at an end section  22  of the line  20  two snap-action elements  26 , which are implemented to be elastically deflectable, are arranged at two opposite positions on the grid structure  28  and thus make it possible during assembly to mount the cage  8  with a spray head  6  incorporated by deflecting it and engaging it in corresponding recesses  24  on the end section  22  of a line  20 . 
     During operation, washing solution passes out of an opening (not shown) arranged in the end section  22  of the line  20 , which solution after overcoming a free path (not shown) strikes the conically implemented central deflector surface  14 , from which the washing solution is directed into the channels  16  formed by the guide elements  18 , which on account of their shape cause the spray head  6  to rotate and the washing solution thus passes out from the channels  16  and applies washing solution to the items to be washed arranged beneath the top spray device  4 . In addition, washing solution passes directly through the cutouts  24  and thus reaches areas directly beneath the spray head  6 , with the result that washing solution can also be applied to items to be washed and cutlery located in this area. 
     LIST OF REFERENCE CHARACTERS 
     
         
           2  Hydraulic system 
           4  Top spray device 
           6  Spray head 
           8  Cage 
           10  Seat 
           12  Shaft journal 
           14  Deflector surface 
           16  Channel 
           18  Guide element 
           20  Line 
           22  End section 
           24  Recess 
           26  Snap-action element 
           28  Grid structure 
           30  Upper 
           32  Underside 
           34  Cutout