Abstract:
A household dishwashing machine of the type having a wash chamber in the form of a drawer, with the drawing being moveable between a lowered to a raised position for facile loading and unloading of the dishes.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates generally to a household dishwashing machine with a drawer lifting mechanism and more particularly to a household dishwashing machine of the type having a wash chamber in the form of a drawer wherein the height of the drawer can be adjusted with a drawer lifting mechanism.  
           [0003]    2. Description of the Related Art  
           [0004]    Household dishwashing machines having the appearance of a cabinet are known. Such dishwashers generally have at least one drawer that forms a wash tub, and if two or more drawers are employed, then usually each drawer functions as a separate wash tub. Cabinet dishwashers are desirable because the drawers are simple to use and the user does not have to manipulate a conventional pull-down door. Furthermore, the cabinet dishwashers have a sleek appearance that integrates well with other cabinet structures in the kitchen.  
           [0005]    Loading and unloading the dish drawer of a cabinet dishwashing machine, however, can be difficult because the drawer can be located at a relatively low position, which may require some users to bend over or reach further than is comfortable.  
         SUMMARY OF THE INVENTION  
         [0006]    The invention relates to a household dishwasher with a drawer lift mechanism that can move the drawer between a conventional initial fill/empty position and a raised position that permits facile loading and a unloading of the drawer.  
           [0007]    Specifically, the invention relates to a dishwasher comprising a housing defining an interior chamber having an open face providing access to the interior chamber, a first drawer is moveably mounted to the housing for movement between a wash position, where the first drawer is disposed inside the interior chamber, and a fill/empty position, where at least a portion of the first drawer extends out of the interior chamber. A dish rack is carried by the first drawer and holds the dishes to be cleaned. A drawer lift mechanism moves the first drawer between the fill/empty position and a raised position above the fill/empty position.  
           [0008]    When the first drawer is in the raised position, the dish rack is located approximately 24-36 inches above a floor on which the dishwasher sets, and/or the drawer lift mechanism raises the first drawer approximately 12-24 inches.  
           [0009]    The dishwasher can optionally comprise a second drawer moveably mounted to the housing for movement between a wash position where the second drawer is disposed inside the interior chamber above the first drawer and a fill/empty position where at least a portion of the second drawer extends out of the interior chamber. When the first drawer is in the raised position, the first drawer is approximately at the same height as the second drawer.  
           [0010]    The first drawer of the dishwasher comprises a bottom wall and a peripheral side wall extending upwardly from the bottom wall to define an open-top wash chamber in which the dish rack is located, wherein the dish rack is removably mounted to the first drawer in the open-top wash chamber.  
           [0011]    The lift mechanism can be a scissor lift operable between a retracted position and an extended position to move the first drawer to the raised position when the scissor lift is in the extended position. The scissor lift can comprise a pair of hingedly connected arms, each arm having a lower end and an upper end, the lower ends being coupled to the housing and the upper ends coupled to the first drawer, and a drive mechanism for rotating the arms about the hinge to move the scissor lift between the retracted and extended positions.  
           [0012]    The drive mechanism comprises a motor-driven lead screw coupled between the arms such that the rotation of the lead screw in a first direction separates the arms to move the scissor lift into the expanded position, and the rotation of the lead screw in a second direction, opposite the first direction, collapses the arms to move the scissor lift into the retracted position. The lift mechanism can further comprise an actuator that automatically moves the drawer between the raised position and the fill/empty position in response to a user-applied force to the drawer.  
           [0013]    The dishwasher can further comprise a drawer slide moveably mounting the first drawer to the housing for slidable movement between the wash and the fill/empty positions, and the lower ends of the arms are mounted to the drawer slide. The drawer slide comprises first and second rails coupled together for relative slidable movement, with the first rail mounted to the housing and the second rail mounted to the drawer, and the lower ends of the arms are slidably mounted to the second rail.  
           [0014]    In another aspect, the invention relates to a dishwasher comprising a housing defining an interior chamber having an open face providing access to the interior chamber. A first drawer is moveably mounted to the housing for movement between a wash position, where the first drawer is disposed inside the interior chamber, and a fill/empty position, where at least a portion of the first drawer extends out of the interior chamber. A second drawer is moveably mounted to the housing above the first drawer for movement between a wash position, where the second drawer is disposed inside the interior chamber, and a fill/empty position, where at least a portion of the second drawer extends out of the interior chamber. A dish rack is carried by the first drawer and holds dishes to be cleaned. A drawer lift mechanism is provided for moving the first drawer between the fill/empty position and a raised position above the fill/empty position.  
           [0015]    When the first drawer is in the raised position, the first drawer is preferably approximately at the same height as the second drawer, and/or the dish rack is located approximately 24-36 inches above a floor on which the dishwasher sets. The drawer lift mechanism preferably raises the first drawer approximately 12-24 inches.  
           [0016]    The dishwasher further comprises a drawer slide that moveably mounts the first drawer to the housing for slidable movement between the wash and the fill/empty positions. The drawer slide can comprise first and second rails coupled together for relative slidable movement, with the first rail mounted to the housing and the second rail mounted to the drawer, and the lower ends of the arms are slidably mounted to the second rail.  
           [0017]    The lift mechanism can be a scissor lift mounted to the drawer slide and operable between a retracted position and an extended position to move the first drawer to the raised position when the scissor lift is in the extended position. The scissor lift can comprise a pair of hingedly connected arms, each arm having a lower end and an upper end, the lower ends being coupled to the drawer slide and the upper ends coupled to the drawer, and a drive mechanism for rotating the arms about the hinge to move the scissor lift between the retracted and extended positions.  
           [0018]    The drive mechanism can be in the form of a motor-driven lead screw coupled between the arms such that the rotation of the lead screw in a first direction separates the arms to move the scissor lift into the expanded position, and the rotation of the lead screw in a second direction, opposite the first direction, collapses the arms to move the scissor lift into the retracted position. The lift mechanism can further comprise an actuator that automatically moves the drawer between the raised position and the fill/empty position in response to a user-applied force to the drawer. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    In the drawings:  
         [0020]    [0020]FIG. 1 is a perspective view of a household dishwasher having a drawer lift mechanism according to the invention, wherein the dishwasher has a first drawer below a second drawer, the first drawer is shown in a fill/empty position, and the second drawer is in a wash position.  
         [0021]    [0021]FIG. 2 is a schematic side view of the household dishwasher of FIG. 1 with the first drawer in the wash position.  
         [0022]    [0022]FIG. 3 is a schematic rear view of the household dishwasher of FIG. 1 with the first drawer in the wash position.  
         [0023]    [0023]FIG. 4 is a schematic side view of the household dishwasher of FIG. 1 with the first drawer in the fill/empty position.  
         [0024]    [0024]FIG. 5 is a schematic side view of the household dishwasher of FIG. 1 with the first drawer in a raised position.  
         [0025]    [0025]FIG. 6 is a schematic side view of a second embodiment household dishwasher of FIG. 1 with an alternative drawer lift mechanism according to the invention, wherein the first drawer is in the fill/empty position.  
         [0026]    [0026]FIG. 7 is a schematic rear view of the household dishwasher of FIG. 6 with the first drawer in the fill/empty position.  
         [0027]    [0027]FIG. 8 is a schematic side view of the household dishwasher of FIG. 6 with the first drawer in a raised position. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    Referring now to the drawings, FIG. 1 illustrates a household dishwasher  10  comprising a housing  12  defining an interior chamber  14  having an open face providing access to the interior chamber  14 . First and second drawers  16 ,  26  are moveably mounted to the housing  12  for movement between a wash position, as illustrated by the second drawer  26 , where the drawer is disposed inside the interior chamber  14  and a fill/empty position, as illustrated by the first drawer  16 , where at least a portion of the drawer extends out of the interior chamber  14 .  
         [0029]    Each of the drawers  16 ,  26  forms a separate wash chamber for washing dishes and the like. Functionally, each drawer  16 ,  26  can be thought of as a separate dishwasher. Although the first and second drawers  16 ,  26  are illustrated as being mounted within the same housing  12  and in a stacked configuration, it is within the scope of the invention for each drawer to have a separate housing and to be arranged in configurations other than a stacked arrangement. It is also within the scope of the invention for any number of drawers, from a single drawer to a plurality of drawers, to be used.  
         [0030]    The first drawer  16  comprises a bottom wall  18  and a peripheral side wall  20  extending upwardly from the bottom wall  18  that define an open-top wash chamber  22  having a dish rack  24  therein. The dish rack  24  is preferably removably mounted to the first drawer  16 . A handle/pull  25  is located on a front portion of the peripheral wall  20 .  
         [0031]    Similar to the first drawer  16 , the second drawer  20  comprises a bottom wall  30  and a peripheral side wall  32  extending upwardly from the bottom wall  30  that define an open-top wash chamber  34  with a second dish rack (not shown) located therein. The second dish rack is preferably removably mounted to the interior of the second drawer  26 . A handle/pull  35  is located on a front portion of the peripheral wall  32 .  
         [0032]    The first and second drawers  16  and  26  are slidably mounted to the housing  12  by a pair of drawer slides  36 . Since the same drawer slides  36  are preferably used for both drawers  16 ,  26 , only the drawer slide  36  for the first drawer  16  will be described, with it being understood the description applies to the drawer slide  36  for the second drawer  26 .  
         [0033]    Each drawer slide  36  comprises a first rail  38  and a second rail  40  coupled together for relative slidable movement by rollers  41  and  43 , which are mounted, such as by journaling, to the first and second rails  38 ,  40 , respectively. The first rail  38  is mounted to the housing  12  and the second rail  40  is coupled to the first drawer  16 , thereby moveably mounting the first drawer  16  to the housing  12  and facilitating movement of the first drawer  16  between the wash and fill/empty positions.  
         [0034]    The preferred drawer slides  36  as described are well known and need not be described further. It should be noted that if further extension of the drawer  16 ,  26  is required, the drawer slides  36  can include more rails to permit the complete extension of the drawer  16 ,  26  beyond the housing  12 . In addition, any other type of drawer slides, which are well known, or any other mechanism suitable for facilitating movement of drawers between the wash and fill/empty positions can be utilized.  
         [0035]    Each drawer  16 ,  26  also comprises a liquid recirculation system  45  for introducing, recirculating, and draining liquid. The type of liquid recirculation system used is not germane to the invention. Any suitable type of recirculation system can be used, such as those disclosed in U.S. Pat. No. 6,447,081, which is incorporated by reference.  
         [0036]    The dishwasher  10  further comprises a drawer lift mechanism  42  for the first drawer  16 . A first embodiment of the drawer lift mechanism  42  is shown in FIGS. 2-5, which do not show the liquid recirculation system  45  for clarity, and comprises identical scissor lifts  44  disposed on opposite sides of the first drawer  16 . Each scissor lift  44  has lower and upper pairs  46 ,  48  of arms  50 ,  52 , which are connected by a hinge pin  54  at their crossing point. Each pair  46 ,  48  have a lower end and an upper end. Rollers  59  are rotatably mounted to the upper ends of the arms  50 ,  52  of the upper arm pair  48 . Similarly, rollers  61  are rotatably mounted to the lower ends of the lower arm pair  46 . The rollers  59  are received in a track/rail  63  on the upper portion of the drawer. The rollers  61  ride on a track/rail  65  formed in an upper portion of the second rail  40 .  
         [0037]    A drive mechanism  64  connects the lower ends of the upper arm pair  48  and the upper ends of the lower arm pair  46  such that the drive mechanism can draw together or move apart the lower ends of the upper arm pair  48  and the upper ends of the lower arm  46  pair to extend and collapse the arm pairs  46 ,  48  and thereby raise and lower the drawer  16 .  
         [0038]    As illustrated, the preferred form of the drive mechanism  64  comprises lead screws  66  mounted on opposite sides of the drawer. Each lead screw  66  carries threaded drive blocks  67 , which are threaded onto the lead screw  66  and which rotatably mount the lower ends of the upper arm pair  48  and the upper ends of the lower arm pair  46 . A motor  68  is coupled to the lead screws  66  by a chain  69  entrained about drive gears  71  mounted to the end of each lead screw  66 . The actuation of the motor  68  drives the chain  69 , which turns the drive gears  71  to rotate the lead screws  66 . The rotation of the lead screws  66  results in the drive blocks traveling toward or away from each other along the lead screws  66  to effect the extension or collapsing of the upper and lower arm pairs  46 ,  48 , respectively. Alternatively, rather than utilizing a single motor  68  and a chain  69 , two motors, one disposed on each side of the drawer  16 , could be used to turn the drive gears  71  and thereby rotate the lead screws  66 .  
         [0039]    In operation, a user desiring to load or unload the first drawer  16  grasps the drawer handle/pull  25  and moves the first drawer  16  in the fill/empty position, as illustrated in FIG. 4 by sliding the drawer  16  on the drawer slides  36 . The drawer handle/pull  25  preferably includes a switch to activate the motor  68  to drive the chain loop  69 , which thereby rotates the lead screws  66  as previously described. As the lead screws  66  are rotated, the threaded drive blocks  67  move towards each other, extending the arm pairs  46 ,  48  as they rotate about the hinge pins  54 , causing the rollers  59 ,  61  to follow the corresponding track/rail  63 ,  65  and thereby elevating the first drawer  16  to a raised position (FIG. 5) above the fill/empty position.  
         [0040]    When the first drawer  16  is in the raised position, the first drawer  16  is sufficiently elevated to accommodate facile loading and unloading of the first drawer  16  by persons with back pain, inadequate flexibility, or other physical limitations. For example, when the first drawer  16  is in the raised position, the dish rack  24  can be located approximately 24-36 inches above a floor on which the dishwasher  10  sets. In terms of the displacement of the first drawer  16 , the drawer lift mechanism  42  can raise the first drawer  16  approximately 12-24 inches. When the dishwasher  10  comprises a second drawer  26 , the first drawer  16 , when in the raised position, can be located at approximately the same height as the second drawer  26 . Different heights and range of movement can be achieved by altering the length of the arms  50 ,  52  or the number of arm pairs  46 ,  48 .  
         [0041]    When the user desires to lower the first drawer  16  to the fill/empty position, the user activates the motor  68  using the switch on the handle  25  to drive the chain loop  69  in the reverse direction, thereby rotating the lead screw  66  in the reverse direction. As the lead screw  66  is rotated in the reverse direction, the drive blocks  67  move away from each other, and each pair  46 ,  48  of arms  50 ,  52  rotate about the hinge pin  54  and move to a retracted position, best seen in FIG. 4, thereby lowering the first drawer  16  to the fill/empty position.  
         [0042]    While it is preferred that the arms  50 ,  52  be connected by the hinge pin  54 , it is not necessary. If the hinge pin  54  is used, the upper and lower ends of the arms  50 ,  52  must be free to move laterally as the scissor lift  44  is extended or collapsed, which requires that a corresponding track/rail be provided to support the movement of the ends of the arms  50 ,  52 . However, if a hinge pin  54  is not used, then the ends of the arms  50 ,  52  not connected to the drive blocks  67  can be rotatably pinned to the drawer and eliminate the need for the track/rail.  
         [0043]    For simplicity, it is preferred that the motor  68  is actuated by a switch located on or around the handle/pull  25 , or the motor  68  can be activated by any other suitable mechanism. For example, force sensors can be coupled to the drawer such that they detect a user-applied lifting/lowering force and will appropriately raise or lower the drawer, depending on the current position of the drawer.  
         [0044]    [0044]FIGS. 6-8 illustrate a second embodiment of the dishwasher with lift drawer. The second embodiment is identical to the first embodiment, except for the type of lift mechanism to raise and lower the drawer. Therefore, like numerals will be used to identify like parts and only the new lift mechanism is described in detail, with it being understood that the description of the relevant portions of the first embodiment applies to the second embodiment.  
         [0045]    The lift mechanism for the second embodiment is also a scissor lift mechanism and comprises identical scissor lifts  70  disposed on opposite sides of the first drawer  16 . Each scissor lift  70  comprises a single pair  72  of crossing arms  74 ,  76  having a lower end and an upper end. Unlike the first embodiment, the arms  74 ,  76  are not connected at their cross over point. Rollers  78  are mounted to the lower ends of the arms  74 ,  76  and are slidably mounted to the second rail  40  of the slide  36 . Unlike the first embodiment, the upper ends of the arms  74 ,  76  are pivotally connected to a crossbar  82 , which is connected to an upper portion of the drawer  16 . A drive mechanism in the form of a linear actuator  86  having a telescoping rod  88  is used to move the arms  74 ,  76  between the extended and collapsed positions. The linear actuator  86  is mounted to the second rail  40  and the telescoping rod  88  is mounted to the crossbar  82 .  
         [0046]    To raise the first drawer  16 , the linear actuator  86  is activated in the same manner as the motor for the first embodiment, and the telescoping rod  88  extends, thereby causing the crossbar  82  to ascend. As the crossbar  82  travels upward, the arms  74 ,  76  move to an extended position as the rollers  78  of the lower ends of the arms  74 ,  76  slide towards each other, thereby elevating the first drawer  16  to the raised position above the fill/empty position. To lower the first drawer  16  from the raised position, the linear actuator  86  is activated, and the telescoping rod  88  retracts, thereby causing the crossbar  82  to descend. As the crossbar  82  travels downward, the arms  74 ,  76  move to a retracted position as the rollers  78  slide away from each other at the lower end, thereby lowering the first drawer  16  to the fill/empty position.  
         [0047]    Lift mechanisms are devices well known to those skilled in the art, and the drawer lift mechanism of the present invention is not limited to the scissor lift mechanisms described herein. The drawer lift mechanism can be of any type suitable for raising and lowering a dishwasher drawer. For example, the lift mechanism can comprise hydraulic, pneumatic, or other types of propelling systems known to those skilled in the art.  
         [0048]    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.