Abstract:
A dishwasher includes a drawer which is slidably mounted in a frame and forms a washing chamber. A lid assembly is mounted to the frame for selectively sealing the washing chamber during a washing operation. A closing mechanism moves the lid assembly from a first or open position to a second or closed position that provides a water-tight seal during a washing operation. The dishwasher is further provided with a latching mechanism including a pivoting door front member, a locking member and a linking bar interconnecting the door front member with the locking member. Manipulation of the pivoting drawer front member causes the locking member to engage/disengage with the lid assembly. The latching mechanism further includes a locking bar and a micro-switch that combine to prevent operation of the dishwasher if the drawer is not properly positioned in the frame.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention pertains to the art of dishwashers and, more particularly, to a latching and sealing mechanism for a drawer-type dishwasher.  
         [0003]     2. Discussion of the Prior Art  
         [0004]     In general, dishwashers having pull-out drawers are known in the art. In some cases, the dishwasher will include an upper, pull-out drawer forming a washing chamber for washing smaller objects, such as glassware, utensils, small plates and the like, and a lower, conventional-type dishwasher. In other cases, the dishwasher will include upper and lower pull-out washing chambers, or just simply include a single pull-out type washing chamber. In any event, each pull-out washing chamber must be provided with a lid with a water-tight seal to prevent washing fluid from leaking from the dishwasher during a washing operation.  
         [0005]     Typically, the lid is pivotally mounted to the dishwasher above the pull-out washing chamber. With this arrangement, the lid is elevated from the washing chamber when the drawer is withdrawn from the dishwasher, and lowered onto the washing chamber when the drawer is inserted back into the dishwasher. This design requires a seal or gasket to be provided on either the lid or the washing chamber. More often than not, the gasket is located about a peripheral portion of the lid.  
         [0006]     In addition to the gasket, a force is required to seat the lid against the washing chamber to ensure a water-tight seal. Manufacturers have developed a variety of methods for establishing a water-tight seal between the lid and washing chamber. In one example, an inflatable gasket is secured about the lid. Once the lid is lowered against the washing chamber, a solenoid activated valve is operated to inflate the seal by delivering an air flow generated by a compressor. In another example, the lid is drawn against the washing chamber through operation of a motor driven worm gear. In either case, the systems required to establish the seal are complex and prone to failure, both of which, in the case of consumer appliances, are undesirable characteristics.  
         [0007]     Based on the above, there still exists a need in the art for an enhanced latching mechanism for a drawer-type dishwasher. More specifically, there exists a need for a latching mechanism that will bias a sealing lid against a washing chamber without requiring additional, complex support elements, such as motors, compressors and the like.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention is directed to a dishwasher including a drawer forming a washing chamber slidably mounted in a frame assembly. The drawer is provided with a lid assembly pivotally mounted to the frame for selectively sealing the washing compartment during a washing operation. The drawer is also provided with first and second spray arms for spraying a washing fluid onto objects within the washing chamber. More, specifically, a first spray arm is located in a bottom portion of the drawer and a second spray arm is mounted to the lid assembly.  
         [0009]     In accordance with a preferred embodiment of the present invention, the lid assembly includes a closing mechanism. More specifically, the closing mechanism includes a four-bar, over-center linkage mounted to the frame for moving the lid assembly between first and second positions. The first position enables the drawer to slide from the frame assembly and the second position forces the lid assembly against the drawer to seal the washing chamber.  
         [0010]     In accordance with the most preferred embodiment, the dishwasher is provided with a latching mechanism to selectively retain the drawer within the frame during the washing operation. More specifically, the latching mechanism includes a pivoting drawer front, a locking member mounted to the drawer and a linking bar interconnecting the drawer front with the locking member. The latching mechanism is operated by pivoting the drawer front, which causes the locking member to engage/disengage a locking pin carried by the lid assembly. A locking bar is provided to engage with the locking member when the drawer is withdrawn from the frame. In addition, a micro-switch is positioned adjacent to a the locking member. The micro-switch further prevents operation of the dishwasher if the drawer is not properly seated within the frame.  
         [0011]     Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is an upper right perspective view of a dishwasher incorporating a latching and sealing mechanism constructed in accordance with the present invention;  
         [0013]      FIG. 2  is a cross-sectional, plan view of the dishwasher of  FIG. 1 ;  
         [0014]      FIG. 3  is a partial, cross-sectional plan view of the dishwasher of  FIG. 2  depicting the latching and sealing mechanism constructed in accordance with the present invention;  
         [0015]      FIG. 4  is a partially exploded, upper right perspective view illustrating the sealing mechanism of the present invention;  
         [0016]      FIG. 5  is a plan view of a compressive link tolerance accumulator provided as part of the sealing mechanism shown in  FIG. 3 ;  
         [0017]      FIG. 6  is a partial plan view of the sealing mechanism of the present invention shown in a raised position;  
         [0018]      FIG. 7  is a partial plan view of the sealing mechanism of the present invention shown in a lowered position;  
         [0019]      FIG. 8  is a partial plan view of the latching mechanism of the present invention shown in a latched position; and  
         [0020]      FIG. 9  is a partial plan view of the latching mechanism of the present invention shown in an unlatched position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]     With initial reference to  FIGS. 1-2 , a dishwasher constructed in accordance with the present invention is generally indicated at  2 . As shown, dishwasher  2  includes a support frame  4  that is arranged below a kitchen countertop  6 . Also below kitchen countertop  6  is shown cabinetry  8  including a plurality of drawers  10 - 12 , as well as cabinet doors  13  and  14 . Although the actual dishwasher into which the present invention may be incorporated can vary, the invention is shown in connection with dishwasher  2  depicted as a dual cavity dishwasher having an upper washing unit  16  and a lower washing unit  18 . As further illustrated, upper washing unit  16  takes the form of a slide-out drawer unit, while lower cavity  18  is illustrated as a conventional-type dishwasher.  
         [0022]     In accordance with a preferred form of the invention, upper washing unit or drawer  16  is shown to include a front wall  20 , a rear wall  21 , a bottom wall  22  and opposing side walls  23 ,  24  that collectively define an upper washing chamber  28 . In a manner known in the art, upper washing chamber  28  is provided with a wire dish rack for supporting various objects, such as dishware, glassware, and the like, to be exposed to a washing operation. Also, upper washing unit  16  is slidably supported within support frame  4  through a pair of drawer support guides, one of which is indicated at  33 .  
         [0023]     With particular reference to  FIG. 2 , upper washing unit  16  is provided with a lid assembly  35  which, as will be discussed more fully below, is provided to selectively seal upper washing chamber  28  during a washing operation. As further shown in  FIG. 2 , upper washing chamber  28  is provided with a plurality of spray arms for directing a washing liquid onto objects placed within washing chamber  28 . Toward that end, an upper spray arm  38  is arranged on lid assembly  35  for directing washing liquid downward onto objects within washing chamber  28 , and a lower spray arm  40  is arranged above bottom wall  22  for directing washing liquid upwardly onto the objects contained within washing chamber  28 . Upper and lower spray arms  38  and  40  are supplied by conduits  42  and  43 , each of which is interconnected to a main or upper supply conduit  45 .  
         [0024]     On the other hand, as shown, lower washing unit  18  is provided with a lower washing chamber  54  having a plurality of spray arms adapted to direct a washing liquid onto articles placed within lower washing unit  18 . As shown, lower washing chamber  54  is provided with an upper spray arm  57  for directing the washing liquid downward onto the articles placed within lower washing unit  18 , as well as a lower spray arm  58  for directing the washing liquid upwardly onto the articles. Upper and lower spray arms  57  and  58  are supplied by respective conduits  60 , and  61  that, along with main supply  45 , interconnect with a pump  64  driven by a motor  66 . Finally, upper and lower washing units  16  and  18  are provided with respective drain portions (not shown) for removing the washing liquid from upper and lower washing chambers  28  and  54  respectively. In general, the structure described above does not constitute part of the present invention, but rather has only been described for the sake of completeness. Instead, the present invention is particularly directed to a latching and sealing mechanism for raising and lowering lid assembly  35  onto washing chamber  28 .  
         [0025]     With particular reference to  FIGS. 3 and 4 , the latching and sealing mechanism of the invention is shown to include a pair of U-shaped support frames  73  and  74 , each of which includes a respective pair of support bars  77 ,  78  and  80 ,  81  interconnected through respective cross pieces  83  and  84 . In accordance with the preferred form of the invention, U-shaped support frames  73  and  74  are provided to support lid assembly  35  for movement relative to upper washing chamber  28 . Lid assembly  35  must be raised in order to permit upper washing unit  16  to be withdrawn from support frame  4 . Toward that end, lid assembly  35  is provided with a sealing or closing mechanism having a pair of linkage assemblies  86  and  87  for selectively raising and lowering lid assembly  35  relative to upper washing chamber  28 . While a variety of linkage assemblies can be utilized, linkage assemblies  86  and  87  are preferably constituted by four bar linkages having an over-center position which, as will be discussed more fully below, biases lid assembly  35  into each of the open and closed positions. Toward that end, linkage assemblies  86  and  87  include first and second pairs of linking members  90 ,  91 , and  92 ,  93 , which are interconnected through respective connecting bars  100  and  101 . In accordance with the most preferred form of the present invention, linking members  90 ,  91  and  92 ,  93  are constituted by compressive link tolerance accumulators which, as will be discussed more fully below, provide a biasing force that aids in retaining lid assembly  35  in its open and closed positions.  
         [0026]     Reference will now be made to  FIG. 5  in describing the specific structure of linking members  90 - 93 . Since the structure of each linking member  90 - 93  is identical, a detailed description of linking member  90  will be made and it is to be understood that linking members  91 - 93  have commensurate structure. As illustrated, linking member  90  includes a first segment  108  slidingly connected to, and maintained in a spaced relationship from, a second segment  109  through a spring  110 . In accordance with the most preferred form of the present invention, first segment  108  includes a guide member  111  and a stop member  112 . Similarly, second segment  109  includes a guide member  114  and a stop member  115 . Preferably, guide members  111  and  114  are provided with respective end stops  117  and  118 . End stops  117  and  118  are adapted to interengage with hook members  120  and  121 , arranged at a terminal end portion of stop members  112  and  115  respectively, to limit the travel of first and second segments  108  and  109 . Finally, each of first and second segments  108  and  109  is provided with a guide block  124 ,  125  having a central opening (not separately labeled) adapted to receive a corresponding one of guide members  111  and  114 .  
         [0027]     With this arrangement, as illustrated in  FIGS. 6 and 7 , linking assemblies  86  and  87  rotate from a first position, wherein lid assembly  35  is biased against upper washing chamber  28 , to a second position wherein lid assembly  35  is elevated from upper washing chamber  28 . As linkage assemblies  86 ,  87  rotate, linking members  90 - 93  begin to compress as linking assemblies  86  and  87  reach an over-center position. Once linkage assemblies  86  and  87  pass the over-center position, spring  110  forces first and second segments  108  and  109  apart causing lid assembly  35  to remain in the respective open or closed position as will be discussed more fully below.  
         [0028]     In further accordance with the preferred form of the present invention, not only is it necessary to seal upper washing unit  16  during a washing operation, it is desirable to prevent activation of dishwasher  2  when lid assembly  35  is in an elevated position. Toward that end, dishwasher  2  is provided with a latching mechanism  140  (see FIGS.  2  and  3 ). As best shown in  FIG. 3 , latching mechanism  140  includes a pivoting door member  142  having a handle or latching member  143 , a locking member  145  and a linking bar  147  that interconnects door member  142  with locking member  145 . In addition, latching mechanism  140  is provided with a locking bar  150  that prevents door member  142  from pivoting to a fully closed position when upper washing unit  16  is open. As best shown in  FIGS. 8 and 9 , locking bar  150  includes a first end  151  engaged by a spring  153  that is carried by side wall  23  of upper washing unit  16 . More specifically, first end  151  extends to a second end  154  through an intermediate portion  155 . As will be detailed more fully below, intermediate portion  155  is provided with a laterally projecting locking pin  157  adapted to engage with locking member  145  when upper washing unit  16  is withdrawn from support frame  4 .  
         [0029]     With continued reference to  FIGS. 8 and 9 , locking member  145  includes a cammed surface  160  having first and second camming members  162  and  163 . Camming members  162  and  163  are used to control the activation of a micro-switch  164  as locking member  145  is rotated about a pivot pin  167 . Micro-switch  164  actually serves as a safety interlock feature that prevents activation of dishwasher  2  unless upper washing unit  16  is fully seated within support frame  4 . That is, as upper washing unit  16  is inserted into support frame  4 , locking member  145  rotates from the position shown in  FIG. 8  to the position shown in  FIG. 9  about pivot pin  167  which, in turn, causes cammed surface  160  to engage micro-switch  164 . When upper washing unit  16  is withdrawn from support frame  4 , cammed surface  160  disengages from micro-switch  164 , thereby creating an open circuit that prevents dishwasher  2  from being activated.  
         [0030]     Actually, in addition to micro-switch  164 , latching mechanism  140  is provided with a second safety lock feature which, as stated previously, prevents door member  142  from being fully seated when upper washing unit  16  is withdrawn from support frame  4 . As best shown in  FIGS. 2-3  and  6 - 9 , locking member  145  is provided with a first pin receiving notch  175  adapted to receive locking pin  157 , and a second pin receiving notch  178  adapted to receive a second locking pin  181  carried by lid assembly  35 .  
         [0031]     With this arrangement, when washing unit  16  is in an operational position as represented in  FIG. 2 , locking member  145  captures locking pin  181  in second pin receiving notch  178  ( FIG. 8 ), thus preventing lid  35  from elevating. In order to shift upper washing unit  16  outward, a force is applied to latching member  143  causing linking bar  147  to rotate locking member  145  so as to disengage or release locking pin  181  from within second pin receiving notch  178 . As locking member  145  is rotated, locking bar  150  shifts forward against the force of spring  153  and locking pin  157  nests within first pin receiving notch  175 . In this position, door member  142  is prevented from rotating toward upper washing unit  16  and upper washing unit  16  can be fully withdrawn from support frame  4  to load or unload dishware or the like.  
         [0032]     In order to return upper washing unit  16  from the position of  FIG. 3  to the position of  FIG. 2 , force is applied to door member  142  to shift upper washing unit  16  into support frame  4  upon support guides  33 . As upper washing unit  16  travels rearward, pin  181  becomes located in second pin receiving notch  178  and engages locking bar  150 . Continued rearward shifting of upper washing unit  16  causes locking bar  150  to shift forward so as to disengage locking pin  157  from first pin receiving notch  175 . At this point, locking member  145  is free to rotate in order to fully capture locking pin  181  and to draw lid  35  downward onto upper washing chamber  16 . As locking member  145  rotates, pin  181  shifts both rearward and downward causing linking members  90 - 93  to initially compress ( FIG. 6 ) and allow linkage assemblies  86  and  87  to reach an over-center position. Once linkage assemblies  86  and  87  pass the over-center position ( FIG. 7 ), spring  110  forces first and second segments  108  and  109  apart, causing lid assembly  35  to be biased against upper washing chamber  16 . With this construction, latching mechanism  140  incorporates both mechanical and electrical safety interlock features. In this manner, it is assured that dishwasher  2  will not activate when lid assembly  35  is in an elevated position.  
         [0033]     Although described with reference to a preferred embodiment of the present invention, it should be readily apparent of one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, while the dishwasher is shown as a combination drawer and conventional model, it should be apparent that incorporation of the present invention in a dual drawer model, as well as a single drawer version, is equally acceptable. In addition, while the latching mechanism is illustrated on only one side of the drawer, a second latching mechanism could be arranged on the opposing side. In general, the invention is only intended to be limited to the scope of the following claims.