Abstract:
A height adjustment mechanism for a dish rack of a dishwasher is provided, having an attachment channel for attaching the dish rack to the dishwasher. A wheel assembly slideably engages the attachment channel at first and second spaced apart locations. The wheel assembly includes engagement features corresponding to a plurality of dish rack heights. A rack mounting assembly is attached to the dish rack and slideably attached to the wheel assembly. A lever is pivotably engaged relative to the rack mounting assembly and is configured to selectively engage one of the engagement features. A biasing element is configured to urge the lever into selective engagement with the engagement features, and the rack mounting assembly may be moved from a first to a second dish rack height position by applying a force to the rack mounting assembly generally perpendicular to the attachment channel. An associated method and system are also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/916,144, entitled Height Adjustment Mechanism for a Dishwasher Rack and Associated Method, filed May 4, 2007, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention relate to dishwashers, and more particularly to height adjustment mechanisms for a rack within a dishwasher and methods associated therewith. 
         [0004]    2. Description of Related Art 
         [0005]    A typical dishwasher includes a washtub that defines a front opening, which is sealed by a door pivoting about a substantially horizontal axis. Dishware to be washed may be positioned onto an upper rack or a lower rack. These racks move horizontally from a load position where at least a portion of the rack may be positioned outside of the washtub to facilitate loading or unloading of dishware, to a washing position wherein the racks are fully within the washtub. Movement of the lower rack is typically facilitated by rollers positioned on opposing sides of the rack that engage supporting surfaces on the washtub and/or the door, when the door is in an open position. The upper rack includes wheels or rollers that engage tracks slideably connected to opposing side walls of the washtub. The wheels or rollers slide or roll within the track, which itself slides in relation to the washtub, thereby allowing the upper rack to move horizontally between a load and a washing position. 
         [0006]    One issue that may be encountered with conventional dishwashers is that the relative vertical positioning of the upper and lower racks is fixed. In some instances, an item needing to be washed may be too large to fit between the upper and lower racks. Alternatively, items needing to be positioned on the upper rack due to temperature or other concerns may be too large to fit between the upper rack and the upper surface of the washtub. Although some have attempted to address this issue by providing mechanisms for adjusting the height of the upper rack within the washtub, the mechanisms may be complicated and/or may require multiple operations to obtain an acceptable height of the rack. Furthermore, some prior art designs can be relatively unstable. Accordingly, an improved rack height adjustment mechanism would be desirable. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The above and other needs are met by the present invention which, in one embodiment, provides a dishwasher having a first side wall and an opposing second side wall. The dishwasher includes a dish rack adapted to support dishware in the dishwasher and a first and a second height adjustment mechanism attached to the dish rack and slideably engaged with the first side wall and the second side wall, respectively, wherein the dish rack is supported by the first and the second adjustable height mechanisms such that the dish rack is moveable in elevation relative to the dishwasher, wherein each of the first and second height adjustment mechanisms includes a wheel assembly adapted to be slideably engaged relative to the respective side wall and including a plurality of engagement features corresponding to a plurality of dish rack heights; a rack mounting assembly attached to the dish rack and slideably engaged with the wheel assembly; a lever pivotably engaged relative to the rack mounting assembly and configured to selectively engage one of the plurality of engagement features associated with the wheel assembly so as to secure the rack mounting assembly at a selected elevation relative to the wheel assembly; and a biasing element configured to urge the lever to pivot against the wheel assembly and into selective engagement with the plurality of engagement features. 
         [0008]    Another aspect of the invention includes a height adjustment mechanism for a dish rack for use with a dishwasher having an attachment channel for attaching the dish rack relative to the dishwasher. The height adjustment mechanism includes a wheel assembly adapted to slideably engage the attachment channel at a first location and a second location spaced apart therefrom, and wherein the wheel assembly includes a plurality of engagement features corresponding to a plurality of dish rack heights; a rack mounting assembly attached to the dish rack and slideably engaged with the wheel assembly; a lever pivotably engaged relative to the rack mounting assembly and configured to selectively engage one of the plurality of engagement features associated with the wheel assembly so as to secure the rack mounting assembly at a selected elevation relative to the wheel assembly; and a biasing element configured to urge the lever to pivot against the wheel assembly and into selective engagement with the plurality of engagement features. 
         [0009]    Another aspect of the invention includes a method for adjusting a height of a dish rack relative to an attachment channel. The method includes the steps of: providing a wheel assembly adapted to slideably engage the attachment channel at a first location and a second location spaced apart therefrom, and wherein the wheel assembly includes a plurality of engagement features corresponding to a plurality of dish rack heights wherein one of said engagement features is a peripheral edge of said wheel assembly; providing a rack mounting assembly attached to the dish rack and slideably attached to the wheel assembly; providing a lever pivotably engaged relative to the rack mounting assembly and configured to selectively engage one of the plurality of engagement features; applying a force to the dish rack generally perpendicular to the attachment channel such that the lever disengages the one of the plurality of engagement features; moving the rack until the lever engages a second one of the plurality of engagement features. 
         [0010]    Aspects of the present invention thus provide these and other advantages, as further detailed herein. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0011]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
           [0012]      FIG. 1  schematically illustrates a front perspective view of a height adjustment mechanism for a dishwasher rack according to one embodiment of the present invention; 
           [0013]      FIG. 2  schematically illustrates a rear perspective view of the embodiment of the present invention shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a section view of the embodiment of the present invention shown in  FIG. 1  including an enlarged view of a lever engaging a mounting plate; 
           [0015]      FIG. 4  is a section view of the embodiment of the present invention shown in  FIG. 1  illustrating the relative positioning of a lever and spring; 
           [0016]      FIG. 5  is an exploded view of a height adjustment mechanism for a dishwasher rack according to an alternative embodiment of the present invention; 
           [0017]      FIG. 6  is an exploded view of a portion of the embodiment shown in  FIG. 5  illustrating an outside rack mounting plate and a wheel assembly; 
           [0018]      FIG. 7  is a front view illustrating the embodiment of the present invention shown in  FIG. 1  with the rack at its lowest position; 
           [0019]      FIG. 8  is a front view illustrating the embodiment of the present invention shown in  FIG. 1  with the rack at an intermediate position; and 
           [0020]      FIG. 9  is a front view illustrating the embodiment of the present invention shown in  FIG. 1  with the rack at its highest position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
         [0022]      FIGS. 1 and 2  illustrate a height adjustment mechanism for a dish rack of a dishwasher according to an embodiment of the present invention, the height adjustment mechanism being generally indicated as numeral  100 . Generally described, this embodiment of the present invention is intended to provide a height adjustment for a dish rack  105  of a dishwasher, wherein the rack may be an upper rack  105  or lower rack, as appropriate. As will be understood by those of skill in the art, an upper dish rack may be slideably mounted relative to the inner side-walls of a dishwasher such that the upper dish rack can move in a substantially horizontal plane from a position inside the dishwasher to a position at least partially outside the dishwasher. In one embodiment, attachment of the dish rack to the dishwasher is facilitated by a pair of C-shaped channels (see e.g.,  FIG. 2A ). Each channel may be secured to an inner side-wall of the dishwasher by two pair of rollers, which maintain the C-shaped channel in a substantially horizontal plane while allowing the C-shaped channel to slide at least partially outside of the dishwasher. 
         [0023]    Referring to  FIG. 1 , the height adjustment mechanism  100  includes a wheel assembly  110 , a rack mounting assembly  130  and a lever assembly  140 . Generally described, the wheel assembly  110  facilitates attachment of the height adjustment mechanism  100  to the dishwasher, and the rack mounting assembly  130  facilitates attachment of the height adjustment mechanism  100  to the dish rack  105 . The lever  140  cooperates with the wheel assembly  110  and the rack mounting assembly  130  to selectively position the dish rack  105  at a desired height. The rack  105  generally includes a height adjustment mechanism  100  engaged on each lateral side thereof. 
         [0024]    The wheel assembly  110  includes a wheel mounting plate  112  and a pair of wheels  120 A-B. The wheel mounting plate  112  has a substantially planar base portion  113  and two substantially planar flange portions  114 A-B positioned at opposite ends of the base portion  113 . The flange portions  114 A-B are within substantially the same plane, which is also substantially parallel to the planar base portion  113 . Attached to each flange portion is a wheel  120 A-B, which is sized to engage a mounting track (not shown) in a dishwasher. In one embodiment, the mounting track is a C-shaped channel and the wheels engage the channel as generally shown in  FIG. 2A . The wheels  120 A-B are aligned such that the rack will be positioned in a substantially horizontal plane. In addition, the wheels  120 A-B are preferably spaced apart so as to support the rack  105  relative to the mounting track. Although the wheels shown in the figures are generally round, one of skill in the art will appreciate that other shapes may be used to engage a dishwasher mounting track. 
         [0025]    The base portion  113  of the wheel mounting plate  112  defines two substantially parallel vertical slots  115 A-B. These slots are sized to cooperate with pins  122 A-B and bushings  124 A-B, which provide a slideable attachment between the wheel assembly  110  and the rack mounting assembly  130 . Generally described, the movement of the rack mounting assembly  130 , and therefore the dish rack  105  in relation to the wheel assembly  110 , is restricted by the movement of the pins  122 A-B and bushings  124 A-B within the slots  115 A-B. In other words, movement of the rack mounting assembly  130  in relation to the wheel assembly  110  is in a direction substantially parallel with the longitudinal axis of the slots  115 A-B. 
         [0026]    The base portion  113  also defines two slots  118 A-B that are spaced apart and oriented such that the longitudinal axes of the two slots  118 A-B are substantially aligned. These slots  118 A-B are positioned to accept a portion of the lever  140  as will be discussed in greater detail below, and are oriented generally perpendicular to slots  115 A-B. 
         [0027]    The base portion  113  further defines an upper locating edge  116  and a lower locating edge  117 . In one embodiment, the lower locating edge  117  as well as the upper edges of the slots  118 A-B of the base portion  113  are configured with a substantially inclined or arcuate flange. As will be discussed later, these locating edges and slots may be selectively engaged by the lever to selectively position the upper dish rack at a desired height. The locating edges and slots may be referred to herein as engagement features. 
         [0028]      FIG. 2  illustrates the rack attachment assembly  130 , which includes an outside rack mounting plate  132  and an inside rack mounting plate  136 . The outside rack mounting plate  132  is positioned on the outside of the dish rack  105 , while the inside rack mounting plate  136  is positioned inside the dish rack  105 . These two mounting plates are secured together using fasteners (not shown) with the dish rack  105  therebetween. 
         [0029]    In the embodiment shown in  FIG. 2 , the outside rack mounting plate  132  includes multiple rack attachment mechanisms  134 , which are U-shaped and sized to engage a wire of the upper dish rack  105 . As will be understood by those of skill in the art, the parallel walls of the U-shaped mechanisms  134  may have complementary scalloped portions such that a wire of the upper dish rack can be retained by snapping it into the scalloped portion between the parallel walls. It should be understood that other types of attachment mechanisms for connecting the outside rack mounting plate  132  to the dish rack may be used in connection with the present invention such as other snap-fit designs or fasteners. 
         [0030]    As shown in  FIGS. 1 and 2 , the wheel assembly  110  and the rack mounting assembly  130  are slideably attached using pins  122 A-B and bushing  124 A-B. Specifically, a portion of pins  122 A-B pass through bushings  124 A-B and slots  115 A-B in the wheel mounting plate  112  before engaging the outside rack mounting plate  132 . In use, the rack mounting assembly  130  can move relative to the wheel assembly  110  in a direction substantially parallel with the longitudinal axis of the slots  115 A-B. 
         [0031]    Referring now to  FIGS. 1-4 , the lever  140  selectively engages engagement features of the wheel mounting plate  112  to allow a user to position the dish rack  105  at a desired height. The lever  140  includes a handle portion  142 , a biasing element interface portion  143  and two engagement arm portions  144 A-B. The handle portion  142  extends above the biasing element interface portion  143  with the two engagement arm portions  144 A-B extending downwardly from the biasing element interface portion  143 . In use, the two engagement arm portions  144 A-B are positioned between the outside rack mounting plate  132  and the inside rack mounting plate  136 . 
         [0032]      FIG. 3  provides a side view of an engagement arm portion  144 A of the lever  140 . Engagement arm portion  144 A extends downwardly with a generally arcuate shape and terminates at free end  145 A. The free end  145 A includes a wedge portion  146 A extending substantially horizontally and sized to engage the slot  118 A in the wheel mounting plate  112 , with the upper end of each wedge portion  146 A being inclined and the lower end being substantially horizontally disposed. The free end  145 A also includes a horizontal stop member  148 A that discourages engagement of the wedge portion  146 A with the wheel mounting plate  112  beyond a predetermined distance whether engaging the slots  118 A-B or the locating edges  116 ,  117 . The engagement arm portion  144 B also extends downwardly with a generally arcuate shape terminating at free end  145 B. Free end  145 B also includes a wedge portion  146 B, which is shaped to engage slot  118 B as generally described with respect to wedge portion  146 A. 
         [0033]    The engagement arm portions  144 A-B are spaced laterally apart with respect to the interaction thereof with the wheel mounting plate  112  so as to provide longitudinal stability for the rack  105  relative to the wheel mounting plate  112 , alone or in combination with the pin  122 A-B, bushing  124 A-B and slot  1 I  5 A-B arrangement previously discussed. 
         [0034]      FIG. 4  illustrates the interaction between the biasing assembly  150  and the lever  140 . As illustrated, the biasing assembly  150  includes a housing  152  connected to the dish rack  105  and a biasing element  154 . In the illustrated embodiment, the biasing element is a coil spring with cantilevered diverging tag ends (i.e., such as the spring used by a clothespin). The biasing element  154  biases the free ends  145 A-B of the lever  140  toward the wheel mounting plate  112 . A force may be applied to the handle portion of the lever causing the lever to pivot about pivot point “P” thereby counteracting the biasing force of the biasing element  154 . This pivoting may disengage the free ends  145 A-B from the locating edges  116 , 117  or the slots  118 A-B as will be discussed in greater detail below. 
         [0035]      FIGS. 5 and 6  illustrate an alternative embodiment of the height adjustment mechanism. This alternative embodiment is generally indicated as numeral  200 . Similar to the embodiments described above, the height adjustment mechanism  200  includes a wheel assembly  210 , a rack mount assembly comprising an outside rack mounting plate  232  and an inside rack mounting plate  236 , and a lever assembly  240 . 
         [0036]    Referring to  FIG. 6 , the wheel assembly  210  includes a wheel mounting plate  212  and a pair of wheels  220 A-B configured substantially the same as the wheel assembly  110  described above. The wheel mounting plate  212  includes a base portion  213  that defines two substantially parallel vertical slots  215 A-B. These slots are sized to cooperate with pins  222 A-B and bushings  224 A-B to provide a slideable attachment between the wheel assembly  210  and the outside rack mounting plate  232 . The wheel mounting plate  212  also includes two substantially planar flange portions  214 A-B. 
         [0037]    One distinction between the wheel mounting plate  212  and the wheel assembly  112  is that the wheel mounting plate  212  includes C-shaped features  219 A-B extending from the planar flange portions  214 A-B that open toward the center of the wheel mounting plate  212 . These C-shaped features are configured to slideably engage the outside mounting plate  232  when in use. This feature provides additional stability to the dish rack by discouraging movement of the outside rack mounting plate  232  relative to the wheel mounting plate  212  in a direction other than parallel with the vertical slots  215 A-B. 
         [0038]    As with the height adjustment mechanism  100 , the wheel mounting plate  212  of the height adjustment mechanism  200  includes features configured to be selectively engaged by the lever assembly  240 . Specifically, the wheel mounting plate  212  defines two slots  218 A-B that are spaced apart and oriented such that the longitudinal axes of the slots  218 A-B are substantially aligned. The wheel mounting plate  212  further defines an upper locating edge  216  and a lower locating edge  217 . 
         [0039]    Turning to  FIG. 5 , the outside rack mounting plate  232  is positioned on the outside of the dish rack  105 , while the inside rack mounting plate  236  is positioned inside the dish rack  105 . These two mounting plates are secured together using fasteners  238 A-B with the dish rack  105  therebetween. The embodiment illustrated in  FIG. 5  does not include a rack engagement mechanism (e.g.,  135 ) as describe above with reference to the height adjustment mechanism  100 ; however, one of ordinary skill in the art will recognize that a rack engagement mechanism  135  could be utilized in the height adjustment mechanism  200  if desired. 
         [0040]    The lever  240  is similar to the previously described lever  140 , in that it includes a handle portion  242 , a biasing element interface portion  243  and two engagement arm portions  244 A-B. The biasing element interface portion defines a recess  247 , which is sized and shaped to receive a wire of the dish rack  105 . In use, attachment bracket  255  and fastener  256  secure the wire of the dish rack  105  into the recess such that the lever  240  can pivot about the wire. 
         [0041]    One distinction between the lever  240  and the lever  140  is that the engagement arm portions  244 A-B of lever  240  are substantially planar as opposed to having an arcuate shape like the engagement arm portions  144 A-B described above with reference to lever  140 . 
         [0042]    The engagement arm portions  244 A-B include free ends  245 A-B. These free ends include wedge portions  246 A-B, which are generally the same shape as wedge portions  146 A-B described with reference to the earlier embodiments. 
         [0043]    The biasing assembly  250  includes a housing  252  and a biasing element  254 . In the illustrated embodiment, the biasing element is a flat spring with one free end engaging the housing  252 , which is attached to the dish rack  105 . As one of ordinary skill in the art will recognize, the housing  252  may be attached to the dish rack through the use of C-shaped recesses formed in the housing that create a “snap” fit with portions of the wire rack or it could be attached using other known or developed fastening mechanisms. The other free end of the flat spring engages the biasing element interface portion  243  of the lever  240  such that the engagement arms  244 A-B of the lever  240  are biased (or pivoted) toward the wheel mounting plate  212 . 
         [0044]    Methods of Use 
         [0045]    In one embodiment of the present invention, an upper dish rack is attached to dishwasher using two adjustable height mechanisms  100 —one on each side. The adjustable height mechanisms allow a user to select one of a plurality of possible upper rack heights. In one embodiment, a user can raise the height of upper rack from one of the lower positions by simply applying an upwardly directed force to the dish rack. The inclined upper end of the wedge portions  146 A-B of the free ends  145 A-B cooperate with the inclined or accurate flanges of the lower locating edge  117  or the upper edges of the slots  118 A-B such that the free ends  145 A-B disengage the engagement features of the wheel mounting plate  112  without having to apply a force to handle portion  142  of the lever  140 . To lower the rack, a user applies a force to the handle portion  142  of the lever  140  on the two adjustable height mechanisms, which disengages the horizontal lower ends of the wedge portions  146  from the engagement features, and then lowers the rack to the desired height. The embodiments illustrated in  FIGS. 1-6  include three possible heights, but one of ordinary skill in the art will recognize that the wheel mounting plate  112  may include additional slots similar to slots  118 A-B to facilitate additional height options. In one embodiment, the locating edges  116 ,  117  may be spaced apart by a distance, for example of about 3 inches, with the slots  118  A-B being disposed about half way therebetween. In such instances, the rack  105  may have about a 3 inch height adjustability range in increments of about 1.5 inches. However, one skilled in the art will appreciate that the actual height adjustability may vary considerably depending on the desired configuration of the dishwasher. For instance, the actual height adjustability may be greater than zero inches, up to about 6 inches or greater, as necessary or desirable. 
         [0046]      FIG. 7  illustrates a height adjustment mechanism  100  at its lowest height position. At this position, the pins  122 A-B engage the lower end of the slots  115 A-B such that the rack mounting assembly and therefore the dish rack itself are supported by the pins  122 A-B and the wheel mounting plate  112 . The upper surfaces of the wedge portions  146 A-B of the lever  140  engage the lower locating edge  117  of the wheel mounting plate  112 . 
         [0047]    To raise the dish rack from the lowest position as shown in  FIG. 7 , a user may apply an upwardly directed force to the rack  105  and/or the rack mounting assembly  130 . As the rack mounting assembly  130  is raised, the geometry of the wedge portions  146 A-B will create a force that counteracts the pivoting force created by the biasing element, thereby allowing the wedge portion to slide away from the lower locating edge  117 . Once free of the lower locating edge  117 , the wedge portions  146 A-B will continue to be biased against the surface of the wheel mounting plate  112  by the biasing element  154  and will slide against this surface as the rack mounting assembly  130  rises. 
         [0048]    Upon reaching the intermediate height position as determined by the height of slots  118 A-B, the wedge portions  146 A-B engage the slots  118 A-B with the horizontal stop members  148  engaging the inner surface of the wheel mounting plate  112 .  FIG. 8  illustrates the height adjustment mechanism  100  in an intermediate position. In this position, the rack mounting assembly and therefore the dish rack is supported by the engagement of the free ends  145 A-B of the lever  140  with the wheel assembly  110 . 
         [0049]    To raise the dish rack to its top position as shown in  FIG. 9  from the intermediate position shown in  FIG. 8 , a user may apply an upwardly directed force to the rack  105  and/or the rack mounting assembly  130 . As the rack mounting assembly  130  is raised, the geometry of the wedge portions  146 A-B will create a force that counteracts the pivoting force created by the biasing element thereby allowing the wedge portions  146 A-B to slide out of slots  118 A-B. Once free of the slots  118 A-B, the wedge portions  146 A-B will be biased against the surface of the wheel mounting plate  112  and will slide against this surface as the rack mounting assembly  130  rises. 
         [0050]    Upon reaching the top height position as determined by the upper locating edge  116 , the wedge portions  146  engage the upper locating edge  116  with the horizontal stop members  148  engaging the inner surface of the wheel mounting plate  112 .  FIG. 9  illustrates the height adjustment mechanism  100  in a top height position. In this position, the rack mounting assembly  130  and therefore the dish rack  105  is supported by the engagement of the lever  140  with the upper locating edge  116  of the wheel mounting plate  112 . In this embodiment, the rack mounting assembly  130  is prevented from traveling beyond a predetermined height by the interaction of the pins  122 A-B and the top of slots  115 A-B. 
         [0051]    In an alternative embodiment, the user applies a force to the handle portion  142  of the lever  140  against the biasing element  154  to disengage the wedge portions  146 A-B of the lever from the wheel mounting plate  112  and then raises the rack mounting assembly  130  and therefore the dish rack  105  to one of the plurality of height positions. 
         [0052]    To lower the rack from either the top height position or the intermediate height position, a user applies a force to the handle portion  142  of the lever  140  as generally shown in  FIG. 4 . This force counteracts the force created by the biasing element  154  and causes the wedge portions  146 A-B of the lever  140  to disengage the wheel mounting plate  112 . The dish rack  105  can then be positioned in a different height position. 
         [0053]    Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, a single engagement arm may be employed or additional of slots may be defined by the wheel mounting plate. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.