Abstract:
The invention relates to a dishwasher having a substantially block-shaped housing and a washing tub. The housing includes a hanging cover and a front side having an opening. The washing tub includes a top having an opening and side walls having upper edges extending parallel to the housing cover. The washing tub is configured to be received and withdrawn -from the housing front side opening and to be fully inserted into the housing during a washing operation. A region of the washing tub bears against a region of the housing during the washing operation. The housing has at least one contact surface contoured to match a surface of the washing tub.

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
       [0001]    This is a U.S. national phase application under 35 U.S.C. § 371 of International Patent Application No. PCT/EP2006/000860, filed Feb. 1, 2006, and claims the benefit of German Patent Application No. 10 2005 008 249.1, filed Feb. 22, 2005, German Patent Application No. 10 2005 008 247.5, filed Feb. 22, 2005, and German Patent Application No. 10 2005 008 248.3, filed Feb. 22, 2005. The International Application was published in German on Aug. 31, 2006 as WO/2006/089622 under PCT Article 21(2). 
     
    
       [0002]    The present invention relates to a dishwasher including a housing which is open at the front side, and including a washing tub which is open at the top, the washing tub being able to be withdrawn from the housing. 
       BACKGROUND 
       [0003]    A drawer-type dishwasher is described in WO 98/33426 A1. The advantages of such a drawer-type dishwasher are described in detail in that document. 
         [0004]    Drawer-type dishwashers have a problem which is caused by the need to seal the upwardly open washing tub so as to prevent egress of wash water. To this end, a liquid-tight contact must be provided between the cover of the housing, or sealing strips extending parallel thereto on the housing side walls, and the edges defining the opening of the washing tub. It is common practice to use flexible seals on the edges and/or on the housing. In order to achieve the sealing effect, one of the companion sealing members must exert a force on the other. In the front and rear regions, this force is provided by the insertion movement which occurs perpendicular to the sealing surface. On the other hand, at the lateral edges, the insertion movement occurs parallel to the two sealing surfaces. Therefore, it is important to provide an movement arrangement to produce a force having a component perpendicular to the lateral sealing surfaces. 
         [0005]    To this end, in one embodiment disclosed in WO 98/33426 A1, the housing cover is moved toward the washing tub toward the end of the insertion operation. In order to effect such lowering, it is necessary to provide a complex adjusting mechanism by which the force resulting from the insertion movement is redirected toward the cover. 
         [0006]    Another embodiment described in WO 98/33426 A1 uses a washing tub which has a greater height at the front than at the rear, so that the edges of the side walls slope downwardly toward the rear. Given a correspondingly sloping cover, or a corresponding sealing strip, it is achieved that the insertion movement is no longer parallel to the sealing edge, and therefore produces a force on the companion sealing members. The slope of the edges results in several disadvantages. First of all, the height of the washing tub decreases, which reduces the capacity thereof. Secondly, remaining water standing on the edges runs to the rear and into the housing. 
         [0007]    Also described in WO 98/33426 A1 are variants that use folding covers, or “endless covers” mounted on rollers, but which have disadvantages in terms of tightness. Also described in WO 98/33426 A1 is the lowering of seals by inflating the seal itself, or an activation device associated therewith. 
       SUMMARY 
       [0008]    It is an aspect of the present invention to provide a structurally simple and yet reliable means for sealing the washing tub within the housing. 
         [0009]    In an embodiment, the present invention provides a dishwasher that includes a housing and a washing tub. The housing may have a substantially block-shape and include a housing cover and a front side with an opening. The washing tub may have a front wall, a rear wall, a top having an opening, and side walls having upper edges extending parallel to the housing cover. The washing tub may be configured to be received and withdrawn from the housing in a drawer-like manner and to be fully inserted into the housing during a washing operation. At least one region of the washing tub may bear against a region of the housing during the washing operation. In at least a region of the upper edges and over approximately an entire length of the upper edges, at least one of an outer dimension of the washing tub may decrease in width from front to rear and an inner dimension of the washing tub may increase in width from front to rear. The housing may have at least one contact surface adapted to match a contour of at least one of the outer dimension and inner dimension of the washing tub. 
         [0010]    In another embodiment, the present invention provides a dishwasher that includes a housing and a washing tub and a seal. The housing has a substantially block-shape and includes a housing cover and a front side having an opening. The washing tub includes a front wall, a rear wall, a top having an opening and side walls having upper edges extending parallel to the housing cover. The washing tub may be configured to be received and withdrawn from the housing in a drawer-like manner and to be fully inserted into the housing during a washing operation. The seal may be disposed on the housing and may bear against the washing tub during the washing operation. In at least a region of the upper edges and over approximately an entire length of the upper edges, at least one of an outer dimension of the washing tub may decrease in width from front to rear and an inner dimension of the washing tub may increase in width from front to rear. The seal may have at least one contact surface adapted to match a contour of at least one of the outer dimension and the inner dimension of the washing tub. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    Aspects of the present invention will now be described by way of exemplary embodiments with reference to the following drawings, using like reference numerals to denote like parts in which, 
           [0012]      FIG. 1  is a schematic perspective view of a dishwasher designed in accordance with the present invention, showing the washing tub in an extended position. 
           [0013]      FIG. 2  is a top view of the washing tub of the dishwasher of  FIG. 1 ; 
           [0014]      FIG. 3  is a top view of the dishwasher of  FIG. 1 , showing the washing tub in an extended position; 
           [0015]      FIG. 4  is a partial section taken along line C-C of  FIG. 3 ; 
           [0016]      FIG. 5  is a top view of the dishwasher of  FIG. 1 , showing the washing tub in a retracted position; 
           [0017]      FIG. 6  is a partial section taken along line D-D of  FIG. 5 ; 
           [0018]      FIG. 7  is a schematic perspective view of another dishwasher designed in accordance with the present invention, showing the washing tub in an extended position. 
           [0019]      FIG. 8  is a top view of the washing tub of the dishwasher of  FIG. 7 ; 
           [0020]      FIG. 9  is a top view of the dishwasher of  FIG. 7 , showing the washing tub in an extended position; 
           [0021]      FIG. 10  is a partial section taken along line B-B of  FIG. 9 ; 
           [0022]      FIG. 11  is a top view of the dishwasher of  FIG. 7 , showing the washing tub in a retracted position; 
           [0023]      FIG. 12  is a partial section taken along line A-A of  FIG. 11 ; 
           [0024]      FIG. 13  is a top view of a dishwasher designed in accordance with the present invention, showing the washing tub in an extended position; 
           [0025]      FIG. 14  is a top view of the dishwasher of  FIG. 1 , showing its washing tub in the position required for the washing operation; 
           [0026]      FIG. 15  is a side view of the dishwasher of  FIG. 1  with the side wall removed (cross-section A 1 -A 1 ); 
           [0027]      FIG. 16  is a partial section through the dishwasher of  FIG. 1  taken along line B 1 -B 1 ; 
           [0028]      FIGS. 17 and 17   a  are side views of the dishwasher of  FIG. 2  with the side wall removed (cross-section C 1 -C 1 ); 
           [0029]      FIG. 18  is a partial section through the dishwasher of  FIG. 2  taken along line D 1 -D 1 ; 
           [0030]      FIG. 19  is a top view of a dishwasher designed in accordance with the present invention, showing the washing tub in an extended position; 
           [0031]      FIG. 20  is a top view of the dishwasher of  FIG. 1 , showing its washing tub in the position required for the washing operation; 
           [0032]      FIG. 21  is a side view of the dishwasher of  FIG. 1  with the side wall removed (cross-section A 2 -A 2 ); 
           [0033]      FIG. 22  is a partial section through the dishwasher of  FIG. 1  taken along line B 2 -B 2 ; 
           [0034]      FIGS. 23 and 23   a  are side views of the dishwasher of  FIG. 2  with the side wall removed (cross-section C 2 -C 2 ); 
           [0035]      FIG. 24  is a partial section through the dishwasher of  FIG. 2  taken along line D 2 -D 2 ; 
       
    
    
     DETAILED DESCRIPTION  
       [0036]    An advantage offered by the present invention is that it provides a simple construction of the housing and washing tub, while at the same time allowing the block shape, or possibly the parallelepiped shape, of the washing tub to be maintained. 
         [0037]    In a first variant, an advantage is achieved by the fact that the washing tub either decreases in width in terms of its outer dimensions from the front to the rear or increases in width in terms of its inner dimensions from the front to the rear, at least in the region of the upper edges over approximately the entire length, and that either the housing or a seal provided on the housing has at least one contact surface which is adapted to match the contour of the washing tub. 
         [0038]    In a first exemplary embodiment of this variant, in which the washing tub decreases in width in terms of its outer dimensions from the front to the rear, at least in the region of the upper edges over approximately the entire length, the upper edges of the washing tub have seals provided thereon which, during the washing operation, bear against a region of the housing which also decreases in width from the front to the rear. Thus, the washing tub, including the seals, can be manufactured very easily, for example, by dual injection molding. 
         [0039]    In one advantageous embodiment, in which the washing tub decreases in width in terms of its outer dimensions, at least in the region of the upper edges over approximately the entire length, seals are disposed in the inner corners formed by the housing side walls and the housing cover, and the width of the region between the contact surfaces of the seals also decreases from the front to the rear. Because the seals are disposed within the housing, they remain protected, and there is little risk of damage by the user of the dishwasher. 
         [0040]    It is also advantageous if the region that decreases in width is inclined inwardly with respect to the remainder of the side walls. In this manner, this region can simply take the form of a bevel provided on the outside of the side wall edges, said bevel having a constant angle but increasing in depth from the front to the rear. 
         [0041]    In a particularly advantageous embodiment, in which the washing tub increases in width in terms of its inner dimensions from the front to the rear, at least in the region of the upper edges over approximately the entire length, the housing cover has seals provided thereon which extend into the interior of the washing tub and which, in terms of their contact surfaces providing the sealing effect, are adapted to match the contours of the washing tub. Because the seals are disposed on the inside of the washing tub, any liquid getting between the seal and the sealing surface is prevented from leaking out of the washing tub, and thus from entering the housing. 
         [0042]    In this embodiment, too, it is advantageous if the region which increases in width is inclined outwardly with respect to the remainder of the side walls, because then it can take the form of a bevel provided on the inside of the side wall edges, said bevel having a constant angle but increasing in depth from the front to the rear. 
         [0043]    In another variant, which has a washing tub whose side walls have upper edges provided with seals, a simple construction is achieved by an movement arrangement which, during the insertion operation, move the upper edge of the seal relative to the upper edge of the washing tub in a direction toward the housing cover. 
         [0044]    The movement arrangement can take the form of guide ribs which are disposed on the housing side walls and slope downwardly from the rear wall of the housing to the housing opening. Alternatively, the movement arrangement can take the form of rollers which are disposed, one behind the other, on the housing side walls and whose axes are located on lines which slope downwardly from the rear wall of the housing to the housing opening. In a third variant, the diameter of the rollers may increase toward the rear wall of the housing. 
         [0045]    It is advantageous for the guide ribs, or the line, to have an inclination of about 1°. 
         [0046]    It is also advantageous if the seals have a portion which is C-shaped in cross-section and embraces the ribs or rollers. This increases the elasticity of the seals, thereby reducing the actuating forces. 
         [0047]    In yet another variant, in which lateral seals provided on the housing bear against the washing tub during the washing operation, a simple construction is achieved by the fact that the seals haves L-shaped portions whose legs which, in the position of use, are horizontal, extend under lateral projections of the washing tub which are horizontal in the position of use, and that the lateral projections slope downwardly from the rear wall to the front wall of the washing tub. 
         [0048]    A particular advantage of this variant is obtained by disposing the seal within the interior of the housing, whereby it is projected from damage resulting from falling items to be washed, or the like. 
         [0049]    A simple construction of such a dishwasher is also achieved by the fact that the lateral projections are formed by wedge-shaped side wall portions of the washing tub which are directed outwardly toward the housing side walls with respect to the remainder of the washing tub. This allows the washing tub to be manufactured as an injection-molded part, without the need to separately attach the lateral projections. 
         [0050]    It is advantageous for the guide ribs, or the line, to have an inclination of about 1°. 
         [0051]    It is also advantageous if the seals have an integrally formed sealing lip which overlaps the upper edge of the washing tub. This prevents liquid from leaking over the edge of the washing tub during the washing operation, and thus from dripping into the housing when the washing tub is in an extended position. Adding such a labyrinth at a position in front of the main sealing plane increases reliability. 
         [0052]    The dishwashers  1  illustrated in  FIGS. 1 and 7  each have a substantially block-shaped washing tub  2  which can be withdrawn from a likewise substantially block-shaped housing  3  in the manner of a drawer in order to be loaded and unloaded. For this purpose, housing  3  is open at front side  4 . Rear wall  5 , side walls  6 , cover  7 , and the bottom, are preferably made of metal and joined together to form the housing shape described above. Sliding guidance of washing tub  2  is provided by telescopic rails and denoted in the figures by reference numeral  18 . 
         [0053]    The washing tub is preferably manufactured as a single injection-molded plastic part and is open at the top. As a consequence of the latter, upper edges  8 . 1 ,  9 . 1  and  10 . 1  are formed on side walls  8 , rear wall  9 , and front wall  10 , respectively. Rear wall  9  preferably has the same height as side walls  8 , but may also have a slightly different height. Front wall  10  is preferably higher than side walls  8  and overlaps housing cover  7 , it being possible for said front wall to be covered with a decorative panel  11 . An important feature for an embodiment of the dishwasher is that edges  8 . 1  of side walls  8  extend parallel to the plane of housing cover  7 . 
         [0054]    In order to prevent wash water from leaking from washing tub  2  into housing  3  during the washing operation, during which tub  2  is fully inserted into housing  3  as shown in  FIGS. 5 and 11 , it is necessary, at least, to seal these two components with respect to each other. To this end, conventional profiled sealing strips can be placed (on the housing and/or on the washing tub) between rear wall  9  of the washing tub and housing rear wall  5  or housing cover  7 , and between front wall  10  of the washing tub and front edge  7 . 1  of housing cover  7 , because at these locations, the required force to be exerted by one companion sealing member on the other in order to achieve the sealing effect is provided by the insertion movement. On the other hand, at lateral upper edges  8 . 1 , the insertion movement occurs parallel to the two sealing surfaces. Therefore, it is important to provide an movement arrangement to produce a force having a component perpendicular to the lateral sealing surfaces. 
         [0055]      FIGS. 1 through 6  illustrate a first variant of such a seal in the region of the side walls, while a second variant is shown in  FIGS. 7 through 12 . In both variants, upper edges  8 . 1  of side walls  8  of the washing tub are provided with bevels  12  which increase in depth T from front wall  10  to rear wall  9  at a constant angle of inclination α, and which form the sealing surfaces, i.e., the regions against which bear the seals  13 . 
         [0056]    In the first variant, which is illustrated in  FIGS. 1 through 6 , bevels  12  are located on the outside of side walls  8 . In  FIG. 2 , bevels  12  are shown in hatched shading. It can be seen that upper edges  12 . 1  of bevels  12 , which at the same time define the upper edges  8 . 1  of side walls  8  of the washing tub, extend inwardly, which is why the washing tub decreases in width in terms of its outer dimensions from front wall  10  to rear wall  9  in this region. In  FIG. 2 , this is illustrated by the width specifications B V  and B H , and it can be seen that B V  is smaller than B H . On the other hand, lower edges  12 . 2  of bevels  12  define a region in which side walls  8  have a width B A  which remains constant. 
         [0057]    Located in the inner corners formed by housing side walls  6  and housing cover  7  are seals  13  (see  FIGS. 4 and 6 ) whose sealing contact surfaces  14  are adapted to match bevels  12 . To this end, seals  13  are provided with contact surfaces  14  which are slanted and in which the cross-sectional area, and thus the width b of contact surfaces  14  itself, increases from the front to the rear. Therefore, the width of the region between left and right seals  13  decreases from the front to the rear. As a consequence of the above-described configuration of the sealing surfaces (bevels  12 ) and of contact surfaces  14 , the sealing surfaces do not contact the contact surfaces  14  when washing tub  2  is in an extended position (see  FIG. 3 ). It is only during the last part of the insertion movement of washing tub  2  (see  FIG. 5 ) that the sealing surfaces come into contact with contact surfaces  14 . This reduces the wear of the seals  13 , because there is hardly any friction between the companion sealing members. Moreover, due to the above-described configuration, the force resulting from the insertion movement has a component which is directed perpendicular to the sealing and contact surfaces  14 , and which therefore provides a sealing effect. The cross-sectional views (see  FIGS. 4 and 6 ) also show that seals  13  each further have a sealing lip  15  integrally formed therewith which extends into the interior of washing tub  2 , thereby providing an initial shield to protect the actual seals  13  from excessive exposure to wash water. 
         [0058]      FIGS. 7 through 12  illustrate a second variant, in which two seals  16  themselves extend into the interior of the washing tub.  FIGS. 7  and show that, here, bevel  12  is located at upper edges  8 . 1  on the inside of side walls  8 . Therefore, upper edges  12 . 1  of the bevel extend outwardly; i.e., the washing tub increases in width in terms of its inner dimensions from the front wall (width B V ) to the rear wall (width B H ). In accordance with the configuration of bevel  12 , the contact surfaces  17  of seals  16  shown in  FIGS. 10 and 12  face outwardly. Otherwise, the sealing effect created during insertion of washing tub  2  ( FIGS. 9 and 11 ) is analogous to the first variant. 
         [0059]    In both variants, it is advantageous if seals  13  and  16 , and the front and rear seals not shown, are injection-molded onto cover  7 . In that case, it may be advantageous to manufacture cover  7  from plastic, or to insert an additional inner cover into metal housing  3 , to be able to use a dual injection molding technique. 
         [0060]    Dishwasher  101  has a washing tub  102  which, as illustrated in  FIG. 13 , can be withdrawn from housing  103  in the manner of a drawer in order to be loaded and unloaded. To this end, tub  102  is disposed in a substantially block-shaped or parallelepiped-shaped housing  103  which is open at front side  104  and has a rear wall  105  opposite thereto. Housing  103  is manufactured from metal or plastic and has mounted on each of its two side walls  106  an outer guide member of a telescopic rail  107  (see  FIGS. 15 and 17 ). 
         [0061]    Washing tub  102  is also block-shaped or parallelepiped-shaped and is open at the top. As a consequence, an upper edge  108  is formed on each wall. Rear wall  109  preferably has the same height as side walls  110 , but may also have a slightly different height. Front wall  111  is preferably higher than side walls  110  and overlaps housing cover  112 , it being possible for said front wall to be covered with a decorative panel  113  in a known manner. The only basic requirement for the embodiment of the dishwasher is that edges  108  of side walls  110  extend parallel to housing cover  112 . Tub  102  is made of plastic, and may be manufactured, for example, as a single injection-molded plastic part. Side walls  110  have recesses formed therein to receive the inner guide members of telescopic rails  107 . The attachment of the inner guide members to side walls  110  may be accomplished in a known manner by screws, integrally formed pins or latching hooks. 
         [0062]    In order to prevent wash water from leaking from washing tub  102  into housing  103  during the washing operation, during which the tub is fully inserted into housing  103  as shown in  FIG. 14 , the region in which upper edges  108  of side walls  110  contact housing cover  112  is sealed. To this end, a seal  115  is mounted on each of upper edges  108  (see  FIGS. 16 and 18 ), for example, by gluing, screwing, or the like. Seal has a first, C-shaped portion  116 , the open region  117  facing side wall  106  of housing  103  and encompassing a guide rib  118 . Alternatively, a plurality of rollers arranged one behind the other may be used in place of guide rib  118 . It is important that the surface facing upper leg  120  of C-shaped portion  116  slope downwardly from rear wall  105  of the housing to the housing opening in front side  104 . In the embodiment shown, said surface is upper surface  119  of guide rib  118 . This slope may be provided by a mounting arrangement which is inclined by an angle a (see  FIG. 17   a ), by wedge-shaped guide ribs, by rollers whose axes are located on a line which slopes downwardly from rear wall  105  of the housing to the housing opening in front side  104 , or by rollers whose diameter increases toward rear wall  105  of the housing. Any of the means described above will cause upper leg  120  of C-shaped portion  116  to be pushed upward during insertion of washing tub  102 . In this manner, a sealing lip  121  integrally formed on this leg  120  is urged into contact with housing cover  112 . Since this contact is made only during the last part of the insertion movement, only small actuating forces are needed, and the seals have little wear. 
         [0063]    Dishwasher  201  has a washing tub  202  which, as illustrated in  FIG. 19 , can be withdrawn from housing  203  in the manner of a drawer in order to be loaded and unloaded. To this end, tub  202  is disposed in a substantially block-shaped or parallelepiped-shaped housing  203  which is open at front side  204  and has a rear wall  205  opposite thereto. Housing  203  is manufactured from metal or plastic and has mounted on each of its two side walls  206  an outer guide member  207  of a telescopic rail (see  FIGS. 21 and 23 ). 
         [0064]    Washing tub  202  is also block-shaped or parallelepiped-shaped and is open at the top. As a consequence, an upper edge  208  is formed on each wall. Rear wall  209  preferably has the same height as side walls  210 , but may also have a slightly different height. Front wall  211  is preferably higher than side walls  210  and overlaps housing cover  212 , it being possible for said front wall to be covered with a decorative panel  213 . The only basic requirement for the inventive embodiment of the dishwasher is that edges  208  of side walls  210  extend parallel to housing cover  212 . Tub  202  is made of plastic, and may be manufactured, for example, as a single injection-molded plastic part. Side walls  210  have recesses formed therein to receive the inner guide members of telescopic rails  207 . The attachment of the inner guide members to side walls  210  may be accomplished by screws, integrally formed pins or latching hooks. 
         [0065]    In order to prevent wash water from leaking from washing tub  202  into housing  203  during the washing operation, during which tub  202  is fully inserted into housing  203  as shown in  FIG. 20 , seals  215  are disposed in corners  216  between housing side walls  206  and housing cover  212 , respectively (see  FIGS. 22 and 24 ). These seals have an L-shaped portion  217  and a sealing lip  218  integrally formed therewith. 
         [0066]    In the upper region, washing tub  202  is enlarged outwardly at its side walls  210 , i.e., toward housing side walls  206 . As shown in the side views in  FIGS. 21 and 23 , these enlargements  219  are wedge-shaped, so that lateral projections  220  are formed which slope downwardly from rear wall  209  to front wall  211  of the washing tub. 
         [0067]    Angle of inclination a is about 1° (see  FIG. 23   a ). Horizontal legs  221  of seals  215  extend under lateral projections  220 . During insertion of washing tub  202 , the inclination causes lateral projections  220  to be reliably pressed against seals  215  during the last part of the insertion movement, thereby providing the sealing effect. As shown in  FIG. 20 , the integrally formed sealing lips  218  overlap upper edges  208  of side walls  210  of the washing tub. Due to the downward pointing tip  222  of sealing lips  218 , a labyrinth-like seal is provided at a position in front of the main sealing plane.