Abstract:
A control board assembly for controlling a home appliance includes a control board having at least one functional component, a control panel engaged with the control board, and a knob comprising a front side, a rear side, a first cylindrical portion extending from the rear side thereof which is coupled to said control panel, and a second cylindrical portion extending from the rear side thereof. The knob is configured to shield the control board from damage.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates generally to home appliances, and more particularly, to an appliance knob mounting system and method.  
         [0002]     Washing machines typically include a cabinet that houses an outer tub for containing water, a perforated clothes basket within the tub, and an agitator within the basket. A drive and motor assembly is mounted underneath the stationary outer tub to rotate the clothes basket and the agitator relative to one another, and a pump assembly pumps water from the tub to a drain.  
         [0003]     Known washing machines or dryers include a control board on which a plurality of control knobs is mounted, and a control chassis assembly is also used. This chassis assembly contains components which provide isolation of forces and limit or eliminate outside contamination. However, when a user imparts transverse and axial forces on the control knobs to operate the washing machine, the forces which transfer to the control board may damage the control board or its components. In addition, during the operation of the washing machine, some liquid may spill on the control board which contaminates the control board.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0004]     In one aspect, a control board assembly is provided for controlling a home appliance. The assembly includes a control board having at least one functional component, a control panel engaged with the control board, and a knob comprising a front side, a rear side, a first cylindrical portion extending from the rear side thereof which is coupled to said control panel, and a second cylindrical portion extending from the rear side thereof. The knob is configured to shield the control board from damage.  
         [0005]     In another aspect, a home appliance is provided that includes a housing and a driving unit received in the housing. The driving unit is configured to provide power to home appliance. The appliance also includes a control unit assembly for controlling the driving unit. The control unit assembly includes a control board having at least one functional component, a control panel engaged with the control board, and a knob having a front side, a rear side, a first cylindrical portion extending from the rear side thereof which is coupled to the control panel, and a second cylindrical portion extending from the rear side thereof. The knob is configured to shield the control board from damage.  
         [0006]     In still another aspect, a method is provided of assembling a control unit utilized in a home appliance for controlling operations thereof. The method including providing a control board with at least one functional component, coupling a rotary shaft to the control board, engaging a control panel with the control board, and providing a knob having a front side, a rear side, a first cylindrical portion extending from the rear side thereof which is coupled to the control panel, and a second cylindrical portion extending from the rear side thereof. The knob is configured to shield the control board from damage. The method further includes coupling the knob to the control panel with the receiving hole receiving an end of the rotary shaft. The knob is configured to shield the control panel from damage. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a perspective view partially broken away of an exemplary washing machine including a cabinet and a cover; and  
         [0008]      FIG. 2  is a cross sectional view of the control board assembly shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0009]      FIG. 1  is a perspective view partially broken away of an exemplary washing machine  50  including a cabinet  52  and a cover  54 . A backsplash  56  extends from cover  54 , and a control board assembly  58  is coupled to backsplash  56 . A lid  62  is mounted to cover  54  and is movable between an open position (not shown) facilitating access to a wash tub  64  located within cabinet  52 , and a closed position (shown in  FIG. 1 ) forming a sealed enclosure over wash tub  64 . As illustrated in  FIG. 1 , machine  50  is a vertical axis washing machine. However, the washing machine exemplified in  FIG. 1  and described herein is only for illustration, and is not intended to be limiting in any aspect. Other types of clothes washers or dryers can also benefit from the spirit of the present invention.  
         [0010]     Tub  64  includes a bottom wall  66  and a sidewall  68 , and a basket  70  is rotatably mounted within wash tub  64 . A pump assembly  72  is located beneath tub  64  and basket  70  for gravity assisted flow when draining tub  64 . Pump assembly  72  includes a pump  74  and a motor  76 . A pump inlet hose  80  extends from a wash tub outlet  82  in tub bottom wall  66  to a pump inlet  84 , and a pump outlet hose  86  extends from a pump outlet  88  to an appliance washing machine water outlet  90  and ultimately to a building plumbing system discharge line (not shown) in flow communication with outlet  90 .  
         [0011]     Control board assembly  58  described below in detail could be utilized in connection with many different types of washing machines or washing dishers, and is not limited to practice in connection with any one particular clothes washer or dryer.  
         [0012]     In the exemplary embodiment, control board assembly  58  includes a control panel  92  and a plurality of input selectors  94  which collectively form a user interface input for operator selection of machine cycles and features. In one embodiment, a display  61  indicates selected features, a countdown timer, and other items of interest to machine users.  
         [0013]      FIG. 2  is a cross sectional view of control board assembly  58  shown in  FIG. 1 . In the exemplary embodiment, control board assembly  58  includes a control board  100  which includes functional components  102  on one side. A rotary switch  104  is attached to the other side of control board  100  and a rotary shaft  106  extends from rotary switch  104 . Control panel board  100  is engaged with control panel  92  by a known technique. Control panel  92  includes a central opening  112  therethrough defined by a central cylinder  114 . Central opening  112  has a predetermined diameter, for example, 20 millimeters. Control panel  92  also defines a slot  116  adjacent central opening  112 .  
         [0014]     In the exemplary embodiment, control board assembly  58  includes a knob shell  200  designed to engage control panel  92 . Knob shell  200  includes a front side having a curved surface  202 , a rear side having a flat surface  204 , and a first central cylindrical portion  206  extending from the rear side of knob shell  200 . Central cylindrical portion  206  is a hollow cylinder. A first keyed receiving hole  208  and a second keyed receiving hole  210  are defined in the central portion of cylindrical portion  206  to receive rotary shaft  106  and at least a part of rotary switch  104 . First receiving hole  208  has a diameter D 1  which is smaller than a diameter D 2  of second receiving hole  210 . Each of receiving holes  208 ,  210  has a specific shape which is complementary to the shape of rotary shaft  106  and rotary switch  104 , such as, cube shaped, triangle shaped, and D-shaped. At least one locking tab  212  extends from a peripheral end of central cylindrical portion  206 . Each locking tab  212  includes a barb or fluke  214  with a slant surface  216  on the end. In one embodiment, a single locking tab extends around the peripheral end. In another embodiment, a plurality of tabs  212  extend around the peripheral end and are separated from adjacent tabs  212  by slots (not shown).  
         [0015]     In the exemplary embodiment, a second cylinder  220  extends from the rear side of knob shell  200 . Second cylinder  220  has a larger diameter than that of first central portion  206 , and surrounds first central portion  206 . A slot  222  is formed between an inner wall  224  of second cylinder  220  and an outside wall  226  of first central portion  206 . In addition, a projecting portion  228  extends from central cylinder  114  and is configured to extend within slot  222 .  
         [0016]     During assembly, control board  100  is connected to control panel  92  as is known in the field. Once control panel  92  is engaged with control board  100 , rotary switch  104  and rotary shaft  106  are received in central opening  112 . Knob shell  200  engages control panel  92  such that first keyed receiving hole  208  aligns with rotary shaft  106 . Knob shell  200  is moved in the direction indicated by arrows A so that at least one locking tab  212  extends into the space between the inner wall (not labeled) of first central cylindrical portion  206  and the outside surface (not labeled) of rotary shaft  106 . During insertion of at least one locking tab  212  into the space, barbs  214  of locking tabs  212  are compressed until locking tabs  214  engage an end  230  of central cylinder  114 . In addition, rotary shaft  106  is firmly received in second keyed receiving hole  210 , and the wall of second cylinder  220  is received in slot  116 . As such, knob shell  200  firmly engages control panel  92 . In addition, cylinder  220 , slot  116 , and control cylinder  114  form a labyrinth seal between knob shell  200  and control panel  92 . Thus, knob shell  200  mounts to control panel  92  and does not directly mount to rotary shaft  106 . Rather, rotary shaft  106  extends into receiving hole  210  and rotates with rotation of knob shell  200  due to the keyed configuration of the end of rotary shaft  106  and receiving hole  210 . When knob shell  200  is rotated by a user, rotary switch  104  is also rotated via rotary shaft  106 , as first keyed receiving hole  208  has a specific shape complementary to the shape of rotary shaft  106 .  
         [0017]     Because the outer diameter of central cylindrical portion of the knob shell interacts with the inner diameter of the central cylinder of the control panel, any transverse or axial force exerted on the knob shell is transferred directly to the control panel. As a result, the control board and its components are protected from possible damage under the action of outside force. Due to the labyrinth seal formed between the knob shell and the control panel, the control board is also protected from contamination which could occur if some liquid is spilled by the user on the control panel. Moreover, it eliminates the traditional control chassis in known washing machines or dish washers.  
         [0018]     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.