Patent Publication Number: US-8528995-B2

Title: Household appliance, particularly dishwasher

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a household appliance, particularly a dishwasher. 
     Household appliances are generally known in which the useable space is closed off by an appliance door. In its closed position, the appliance door can be arranged on both sides between frame parts of the household appliance. 
     In such a closed position the correctly-positioned arrangement of the appliance door is of importance in order to retain an even gap dimension between the appliance door and the frame parts. An even gap dimension guarantees inter alia that the inner side of the appliance door is reliably in sealing contact with a seal enclosing the loading opening of the useable space. 
     Maintenance of the gap dimension is especially difficult with dishwashers, of which the washing container opening is surrounded by a plastic frame. The plastic frame has a reduced rigidity compared to a steel frame. Thus a tilting of the dishwasher can result in a deformation of the plastic frame, whereby sufficient coverage of the inner side of the appliance door by the sealing element provided on the plastic frame is no longer guaranteed. To bring about a correction of the alignment of the appliance door to the washing container opening essentially mushroom-shaped introduction aids are inserted into holes. However this increases the assembly effort involved. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to provide a domestic appliance in which the appliance door, in its closed position, with reduced assembly effort, is in reliable sealing contact with a sealing element. 
     The invention is based on a household appliance, especially a dishwasher, at least featuring a container for receiving goods, especially dishes, to be treated, having a container opening able to be sealed with a appliance door, at least sections of which are assigned stiffening means to increase the rigidity of the container in the area of the container opening, having at least one centering element through which, when the appliance door is closed, an alignment of the appliance door to the container opening is able to be effected. 
     In accordance with an exemplary embodiment of the invention, the reinforcement means and the at least one centering element are embodied in a uniform material and/or in one piece as a plastic profile section, especially in a plastic injection-molding process. When moved into its closed position the appliance door is thus centered in the correct position by means of the centering element, which guarantees a sufficient coverage between the appliance door and the sealing element. 
     Preferably there is provision, in the closed position of the appliance door, for there to be stiffening means arranged between at least two opposite sections of the container opening. This two-sided arrangement ensures especially reliably that the appliance door is aligned in relation to the opening such that an optimum sealing effect is provided. 
     Further there is preferably provision for the stiffening means to be embodied as frame parts at least partly surrounding the container opening. For example the frame parts can be arranged as a U shape on three sides of an essentially rectangular container opening and thus at the same time bring about a mechanical stiffening of the container in the area of the container opening. 
     There is also preferably provision for the at least one centering element to define a gap dimension (a) between the appliance door and the stiffening means. A reliable function of the seal and also a problem-free actuation of the appliance door are thus guaranteed. 
     In its closed position, the appliance door can be submerged between delimiting sides of the device-side frame parts facing towards each other until it makes sealing contact with the sealing element. The inventive centering ensures a trouble-free sealing contact between the inside of the door and the sealing element. 
     Especially in the case of a dishwasher the frame parts can form part of a loading opening of a frame enclosing the washing container, especially a plastic frame. 
     In the event of it being formed as an integral part onto the frame part, the centering element can be a bulge projecting from the frame part. The bulge can preferably not only be rotation-symmetrical but can also be elongated in the form of a strip in the depth direction of the household appliance. This guarantees a reliable guidance of the sides of the appliance door between the two frame parts during a closing movement. 
     The sealing element surrounding the front-side useable space opening can be held in a sealing groove. This groove in its turn can be molded onto the frame parts as an integral component. The sealing groove can be designed to be open at the front. 
     When the plastic frame with integrated centering element is manufactured, its geometry is to be designed so that no undercuts on the plastic frame prevent a demolding movement of the injection molding tools. Against this background it is preferred that the centering element formed onto the delimiting side of the plastic frame extends directly to a section protruding from the delimiting side. In this way no undercut is formed between the centering element and the protruding section. The section protruding from the delimiting side can be a step for example on which the sealing element sits. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention is described below with reference to the enclosed figures. 
       The figures show: 
         FIG. 1  in a perspective view as a household appliance, a dishwasher with its door half open; 
         FIG. 2  a part sectional diagram along cut line I-I shown in  FIG. 1 ; and 
         FIG. 3  in a cross-sectional view of plastic injection-molding tools which delimit an injection-molding chamber for forming a plastic frame. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
       FIG. 1  shows a perspective view of a dishwasher as a household appliance, the front door  1  of which is shown half open. The dishwasher has as its useable space a washing container  3  made of stainless steel plate. 
     The washing container  3  is connected at its front loading opening to a plastic frame  5 . This encloses the front loading opening and features two lateral vertical frame parts  7  which are connected by a horizontal upper frame part  9 . 
     The appliance door  1  of the dishwasher is formed in the known way from a front outer section  11 , on which a decor panel  12  may be provided, and an inner door section  13  made of deep-drawn metal which in accordance with  FIG. 2  is connected by screws  15 . The inner part  13  of the appliance door  1  has at least partly surrounding, deep-drawn side pillars  17  at its edges. In a closed position of the appliance door  1  the side pillars  17  of the door inner section  13  are submerged between delimiting sides  19  of the frame parts  7 ,  9  of the plastic frame  5  facing towards each other. 
     The outer edge sides  21  of the side pillars  17 , in the closed position of the appliance door  1 , re spaced away from the delimiting sides  19  of the frame parts  7 ,  9  by a gap dimension a, as is indicated in  FIG. 2 . In  FIG. 2  the appliance door  1  is shown in an enlarged sectional view with the side pillar  17  submerged around halfway into the plastic frame  5 . 
     When the appliance door  1  is completely submerged between the frame parts  7 ,  9  the side pillars  17  of the inner part of the door  13  rest with their front sides  23  in sealing contact with a sealing element  25  which is provided on the delimiting side  19  of the plastic frame part  5  and surrounds the loading opening of the washing container  3 . In  FIG. 1  the sealing element  25  is merely indicated as a dotted and dashed line. 
     The plastic frame  5  in accordance with  FIG. 2 , has a basic body  24  embodied in cross-section as a U-shaped profile, in the hollow space of which open to the outside stiffening ribs run in parallel to the two opposite U arms  26  of the basic body  24 . At its end facing away from the front inside the basic body  24  is extended via a step  33  towards the inside with a connecting flange  34  into the usable space of the washing container  3 . This is overlapped in the depth direction x by the stainless steel plate of the washing container  3  and connected by means of molded-on connecting bolts  36  to the washing container  3 . 
     The connecting flange  34  is offset inwards by the step  33  in relation to the basic body  24  of the plastic frame  5 . In addition the connecting flange  34  is extended by a wall section  35  to the front side of the appliance which is in parallel to the delimiting side  19  of the plastic frame  5 . Between the wall section  35  and the delimiting side  19  of the plastic frame  5  a sealing groove  27  is formed which extends along the frame parts  7 ,  9  and is open on its front side. 
     The sealing element  25  is inserted into the sealing groove  27  open to the front molded on the plastic frame  5 . The sealing element  25  is shown undeformed by a dashed line in  FIG. 2 . Accordingly the sealing element  25  has an upper sealing section  28  which is roughly tube shaped, which protrudes from the sealing groove  27  as well as adjoining this a sealing shaft  29  inserted into the sealing groove  27 . The sealing groove  27  is molded with its groove base, which is formed by the step  33 , directly onto the delimiting sides  19  of the plastic frame  5 . 
     In the two opposite upper corner areas of the plastic frame a centering element  37  is provided in each case on the delimiting side  19  of the lateral frame parts  7 , of which only one element is shown in  FIG. 1 . The centering element  37  is integral with the frame part  7  and is embodied as a bulge projecting by a height h inwards from the delimiting side  19 . The centering element  37  is embodied in accordance with the figures in the shape of a strip in a depth direction x and extends into the sealing groove  27 , whereby good lateral guidance of the appliance door  1  is guaranteed during a closing movement. 
     As emerges especially from  FIG. 2 , the strip-shaped bulge  37  in this case merges directly into the groove base  33  of the sealing groove  27 . Such a geometry of the centering element  37  is especially advantageous for producing the plastic frame  5  in an injection molding process, which is illustrated with reference to  FIG. 3 . 
       FIG. 3  shows the injection molding tools  39 ,  40 ,  41  together delimit an injection molding chamber  43 , with which the plastic frame  5  with integrated centering element  37  will be formed. 
     The injection molding tool  39  is of importance in conjunction with the inventive centering element  37  integrated into the plastic frame  5 . The injection molding tool  39  adjoins the further injection molding tools  40 ,  41  via demolding planes E and has a protrusion  45  with which the sealing groove  27  for the sealing element  25  is formed. 
     The injection molding tool  39  has a substantially flat molding surface  47  with which the delimiting sides  19  of the plastic frame  5  facing inwards are formed. Provided in the molding surface  47  is a channel-shaped indentation  49  which forms the centering element  37 . The indentation  49  runs at a constant depth which is identical to the height h of the centering element  37  up to the end face side of the mold projection  45 . With the geometry of the centering element  37  on the plastic frame  5  shown no additional undercuts between the centering elements  37  and the groove base  33  are thus produced, which would make the injection molding method more difficult. 
     After molding of the plastic frame  5  is completed the injection molding tool  39  can thus be pushed in the demolding direction I out of the sealing groove  27 , without undercuts on the delimiting side  19  of the plastic frame  5  having to be overcome. 
     Accordingly, after successful molding, the other two injection molding tools  40 ,  41  can also be moved apart in the demolding direction I. 
     As further emerges from  FIG. 2  and  FIG. 3 , a holder section  46  projecting into the sealing groove  27  is provided on the wall section  35 . The holder section  46  secures the sealing element  25  inserted into the sealing groove  27  and is provided on the free, front-side end of the wall section  35 . Thus an undercut is formed by the holder section  46 . 
     The wall section  35  is however molded sufficiently elastically flexible on the plastic frame  5 . With a demolding movement of the injection molding tool  39  the wall section  35  with its undercut can thus deflect elastically. This means that the demolding process is easily possible. 
     By contrast with the elastically flexible wall section  35 , the rigidly embodied basic body  24  of the plastic frame with its delimiting side  19  cannot yield elastically, so that on the rigid basic body  24  undercuts on the delimiting side are to be avoided. 
     In the event of the dishwasher being in a tilted position the plastic frame  5  can become distorted. In order to still guarantee in this case an operationally-secure sealing contact between the door inner section  13  and the sealing element  25 , during a closing movement of the appliance door  1 , there is automatic centering in the closed position of the appliance door  1  within the plastic frame  5 . 
     This guarantees an even gap dimension a between the inner section  13  of the appliance door  1  and the delimiting sides  19  of the plastic frame  5 . The positionally-correct arrangement of the appliance door  1  in the closed position also guarantees the functional safety of the door lock. 
     LIST OF REFERENCE SIGNS 
     
         
           1  Appliance door 
           3  Washing container 
           5  Plastic frame 
           7  Lateral frame parts 
           9  horizontal frame part 
           11  Front outer door section 
           13  Inner door section 
           15  Screw connection 
           17  Side uprights 
           19  Delimiting sides 
           21  Outer edge sides 
           23  Front side 
           24  Basic body of the plastic frame  5   
           25  Sealing element 
           26  U-arms of the plastic frame 
           27  Sealing groove 
           28  Sealing section 
           29  Sealing shaft 
           33  Step 
           34  Connecting flange 
           35  Wall section 
           36  Connecting bolts 
           37  Centering element 
           39 ,  40 ,  41  Injection molding tools 
           43  Injection molding chamber 
           45  Projection 
           46  Holder section 
           47  Forming surface 
           49  Channel-shaped indentation 
         a; Gap dimension 
         b; Height 
         x Depth direction 
         E Demolding plane 
         I Demolding direction