Abstract:
A console switch assembly for appliances provides a rotatable electronic switch having a rotational range constrained by a cutout in the control panel to which the switch is mounted. The cutout most simply may be a sector of a circle having a different angular range which constrains a projecting tooth on the shaft of the switch or knob attached to the shaft of the switch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on provisional application 60/540,471 filed Jan. 30, 2004 and entitled Method for Setting Switch Travel During Final Assembly into Product and claims the benefit thereof. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
     The present invention relates to selector switches for appliances such as washing machines, and in particular to a selector switch having the number of selector positions determined by a cutout in the panel to which it is mounted. 
     Appliance manufacturers often want to offer different models of a given appliance for different market segments. For example, a manufacturer may offer a high-end washing machine with eight different water level settings, a mid-range washing machine with six different water level settings, and a low-end washing machine with three different water level settings. 
     Each water level setting may be selected by moving a selector switch to a different position. In this case, the three models described above would require three different switches, an eight-position, a six-position and a three-position switch. Designing, manufacturing and stocking three different switches significantly increases the cost of manufacture of the machines. 
     It is generally known to produce rotary switches having removable internal stops that can control the range of rotation of the switch and thus the number of switch positions. While this reduces the number of switches that must be manufactured, such switches require a separate reconfiguration step, and as a practical matter, must be preconfigured and then separately stocked so as to be ready for installation and yet not to be placed into the wrong appliance. 
     Ideally, a method could be found for providing multiple switches for multiple models of an appliance without increasing manufacturing complexity or requiring stocking of separate configurations or time consuming additional manufacturing steps. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a rotary selector switch whose rotational range is programmable, not by internal stops, but by a cutout in the console of the appliance to which the switch is mounted. The cutout is intrinsic to the appliance itself, eliminates the possibility of a misconfigured switch being inserted into an appliance. The switches need not be preconfigured and no additional manufacturing steps are added. 
     Specifically, the present invention provides an appliance console assembly having a console panel presenting a face to the user of the appliance and having a cutout consisting of a shaft aperture and a rotational limit cutout. A control, having a shaft rotatable to provide a predetermined number of electrically detectable rotational control positions, supports a stop rotationally interfering with the rotational limit cutout when the control is mounted on the console with the shaft passing through the shaft aperture. The interference between the stop and the rotational limit cutout limits the rotation of the shaft to less than all the rotational control positions. 
     Thus it is one object of at least one embodiment of the invention to provide a selector switch that may change its number of selector positions depending on the console into which it is assembled. 
     The stop may be a tooth formed on the shaft, the tooth extending radially therefrom. Alternatively, the stop may be on a tooth formed on a knob affixable to the shaft with the tooth extending axially from a rear side of the knob. 
     It is thus another object of at least one embodiment of the invention to provide simple and flexible methods of using a cutout in the console to program the range of the switch. 
     The rotational limit cutout may be substantially a circular sector. 
     Thus it is another object of at least one embodiment of the invention to provide a simple cutout shape that may be easily fabricated. 
     The console may be a metal sheet providing a portion of a housing for the appliance. 
     It is thus another object of at least one embodiment of the invention to provide a switch that is well suited to standard appliances such as washing machines and dryers in which the cutout can be incorporated into a pre-existing part. 
     The console panel may have multiple cutouts and controls inserted into the cutouts and may have different rotational ranges. 
     Thus it is an object of at least one embodiment of the invention to allow a single switch to be used in multiple locations on an appliance with different functions. 
     Alternatively, the invention may allow multiple appliances having different numbers of switch-selectable features to be manufactured by providing on each appliance different rotational limit cutouts sized according to different numbers of switch-selectable features for each appliance. A standard control affixed at each cutout can thus provide different numbers of rotational control positions as determined by the console to which it is attached. 
     Thus it is another object of at least one embodiment of the invention to reduce the parts required to provide for a range of model types. 
     These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified perspective view of a top-loading washing machine such as may represent a number of different models and/or which may have a number of different selector switches using the present invention; 
         FIG. 2  is an exploded perspective view of a switch console assembly of the present invention showing a shaft aperture and rotational limit cutout in the console and showing two alternative stops, one attached to a shaft of the control and the other attached to the rear of a knob affixed to the shaft, both for limiting rotational range of the control; 
         FIG. 3  is a front elevational view of the console of  FIG. 1  showing two rotational limit cutouts on the same or different machines for programming a standard selector switch for three or four positions, respectively; and 
         FIGS. 4   a  and  4   b  are cross-sectional views taken along line  5 — 5  of  FIG. 2  showing the position of the stops of the knob or shaft with the rotational limit cutout. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIG. 1 , an appliance  10  such as a top-loading washing machine may provide for a housing  12  including a console  14 , the latter providing a control surface facing the user and having a number of selector controls  16  used to select operating modes of the appliance  10 . The housing  12  and console  14  may be, for example, constructed of coated steel or the like. 
     Referring to  FIG. 2 , a shaft aperture  18  may be cut in the console  14  to permit the shaft  22  of a selector control  16  to pass from the rear side of the console  14  through to a front face of the console  14  accessible by a user. A rotational limit cutout  26  surrounds a portion of the shaft aperture  18  and will typically approximate a sector of a circle centered on the shaft aperture  18 , and thus will be radially asymmetric about an axis  28  of the shaft  22 . As used herein, radially asymmetric means that an arbitrary line through the axis  28  will not divide the rotational limit cutout  26  into two substantially mirror image portions. 
     In a first embodiment shown in  FIGS. 2 and 4   b , the shaft  22  may have a radially extending tooth  30  that may fit into the rotational limit cutout  26  when a switchbox  24  of the selector control  16  is mounted at the rear of the console  14  with the shaft  22  projecting through the aperture  18 . As the shaft  22  is turned, the tooth  30  swings through the rotational limit cutout  26 , stopping at a clockwise and counterclockwise position by interference between the tooth  30  and the radial walls of the rotational limit cutout  26 . 
     The shaft  22  may have a flat  32  fitting within a corresponding hole  34  with a flat  38  in a knob  36  and serving to rotationally key the shaft  22  with respect to knob  36 . The knob  36  may be press fit or otherwise attached to the shaft  22  to rotate therewith. 
     In a second embodiment shown in  FIGS. 2 and 4   a , the knob  36  may have an axial tooth  40  extending rearwardly from the rear side of the knob  36  into the rotational limit cutout  26  to operate in a manner similar to that of tooth  30 . 
     Referring to  FIGS. 2 and 3 , the front face of the console  14  may have indicia  19  corresponding to particular operating modes of the appliance  10  that may be selected by the selector control  16  as it moves through a range of control positions. The switchbox  24  typically provides internal electrical contacts controlled by a rotational position of the shaft  22  to different control positions, the contacts providing electrical signals over wires  25  indicating the control positions according to methods well known in the art. The switchbox  24  may provide detent positions at each control position. The present invention contemplates the use of a switchbox  24  having a standard number of control positions greater or equal to the largest number of control positions required of similar selector controls on an individual appliance  10  or on different models of an appliance  10 . 
     Referring now to  FIG. 3 , in one embodiment, an extreme counterclockwise rotation of the knob  36 , the tooth  30  or  40  will abut a radial wall  44  of the rotational limit cutout  26 , providing a stop preventing further rotation of the shaft  22  in a counterclockwise direction. At this time an indicator  45  on the knob  36  may point to a first indicia  19   a . Alternatively or in addition, this stop may be provided by a stop mechanism internal to the switchbox  24 . 
     Clockwise rotation of the shaft  22  through at least a subset of the control positions may then be accomplished with the tooth  30  or  40  passing through the sector of the rotational limit cutout  26  to align with indicia  19   b  at a detent and corresponding control position. Further clockwise rotation can be performed until the tooth  30  or  40  (shown by dotted lines) abuts radial wall  46  of the rotational limit cutout  26  and is stopped thereby. At this time an indicator  45  on the knob  36  may point to a third indicia  19   c.    
     The same selector control  16 , when used with a second rotational limit cutout  26 ′, may allow for further clockwise rotation to additional indicia  19   d  and thus a rotation of the shaft  22  through a greater angular extent of the rotational limit cutout  26 ′. In this way, the same selector control  16  may provide for two ranges of selection on a single machine or two ranges of selection on different models of the same machine. 
     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.