Abstract:
A cooking appliance includes a cooktop having at least one heating element and a controller capable of automatically performing a cooking process by operating the heating element at multiple power levels for multiple time periods. More specifically, upon activation, a consumer, through manipulation of a control, can select an initial power level and an initial time duration for the initial power level. Once the initial power level is selected, a second power level and second time duration may be selected. With this arrangement, the controller will operate the heating element at the initial, high power level for the first time duration. Once the initial time period has elapsed, the controller automatically lowers the temperature of the heating element to finish the cooking process for the second time duration.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention pertains to the art of cooking appliances and, more particularly, to a cooking appliance including a control for operating a heating element at multiple power levels for multiple time periods.  
           [0003]    2. Discussion of the Prior Art  
           [0004]    In general, establishing a selected power level for a heating element in a cooking appliance is known. However, maintaining the selected power level for the entire duration of a cooking process is not always desirable. Specifically, when cooking rice, pasta or other liquid based food items, it is often necessary to bring a liquid to a boil using an initial, high power setting and thereafter simmer at a second or lower power setting for a prescribed period. In today&#39;s fast paced society, there is seldom time to continuously monitor the contents of a pot. Often times the pot will boil over, causing the contents to run onto the heated surfaces of a stove. Other times, the pot is left to boil for so long that the contents boil away, leaving behind a charred mess.  
           [0005]    The prior art teaches a variety of methods for providing a more convenient means of cooking food on a cooktop. One example is provided by U.S. Pat. No. 5,746,114 disclosing an intelligent cooking system. The cooking system includes various cooking implements, such as pots and pans, each having an associated temperature monitor. The system also includes a cooktop having a plurality of burners and a controller that is linked between the cooktop and the temperature monitors to maintain a desired temperature in the associated pot or pan. While effective, this system is large, complex and expensive. In the highly competitive field of cooking appliances, increased cost and complexity can be significant, disadvantageous features.  
           [0006]    Another method disclosed in the prior art is embodied in U.S. Pat. No. 6,236,630 directed to an acoustic sensing system for detecting boiling in a particular cooking implement. As disclosed, an acoustic sensor is mounted in a cooktop range and configured to detect acoustic frequencies that are characteristic of emissions resulting from heating and boiling of water. While effective to a large extent, not all cooking processes include a boiling stage. In addition, as with the previous method, there are both high costs and reliability concerns with this system.  
           [0007]    Based on the above, there exists a need in the art for a cooking appliance including a cooktop and a controller capable of establishing multiple power levels for at least one heating element of the cooktop, with each power level having an associated time duration of operation. More specifically, there exists a need for a cooking appliance having a controller that can establish an initial high power level for a first time period of a cooking operation and then automatically lower to a second power level for the remainder of the cooking operation.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention is directed to a cooking appliance having a cooktop including at least one heating element, a control panel having at least one control element and a controller linked between the at least one heating element and the control element. More specifically, the at least one control element is associated with establishing a desired power level for the at least one heating element. In accordance with a preferred embodiment of the present invention, the controller is adapted to establish first and second settings for the at least one heating element. Preferably, the first setting establishes an initial power level for a first selected time period of a cooking operation, while the second setting establishes a second, lower power level for the remainder of the cooking operation. With this arrangement, the cooking operation is conducted without requiring constant monitoring by a consumer.  
           [0009]    The cooking appliance, in the most preferred embodiment, includes first and second sets of slew buttons arranged on the control element. More specifically, the first set of slew buttons includes a first slew button for selecting the power level and a second slew button for selecting the time period. The second set of slew buttons includes an up arrow slew button and a down arrow slew button. With this arrangement, a consumer can activate the heating element and, through manipulation of the up and down arrow slew buttons, establish a desired initial heating element temperature that functions as a pre-heat process, or simply to establish an initial high cooking temperature.  
           [0010]    Once the initial power level is selected, manipulation of the time slew button will establish a desired time duration for the initial power level. Once the initial power level and initial time are selected, following similar steps, a second or final power level can be established for completing the cooking operation. If a user fails to select a second power level, the controller will preferably default to a predetermined lower power setting. In accordance with the most preferred form of the invention, the second power level must be lower than the initial power level as the control will not permit selection of a higher, second power level.  
           [0011]    Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments 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]    [0012]FIG. 1 is an upper right perspective view of a cooking appliance including a cooktop having a plurality of control elements arranged on a control panel constructed in accordance with the present invention;  
         [0013]    [0013]FIG. 2 is an enlarged, plan view of the control panel and the plurality of control elements of FIG. 1;  
         [0014]    [0014]FIG. 3 is an enlarged, plan view of one of the plurality of control elements constructed in accordance with one embodiment of the present invention; and  
         [0015]    [0015]FIG. 4 is an enlarged, plan view of a control element constructed in accordance with a second embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    With initial reference to FIG. 1, a cooking appliance  2 , generally taking the form of an oven range, includes a cabinet shell  4  provided with a cooktop  6 . As illustrated, appliance  2  constitutes a free-standing electric range such that cooktop  6  is provided with a plurality of electric heating elements or zones  10 - 14 . At this point, it should be noted that, although appliance  2  is shown to constitute a free-standing range, the invention is equally applicable to various other types of cooking appliances including slide-in ranges, kitchen island cooktops, and the like.  
         [0017]    In a preferred embodiment, appliance  2  includes an oven  20  having an interior oven cavity  22 . In a manner known in the art, oven  20  has associated therewith a door  24  which can be pivoted at a lower portion  26  by means of a handle  28 . Door  24  preferably includes a window or transparent zone  30  for viewing the contents of oven  20  when door  24  is closed. In a manner also known in the art, appliance  2  includes a drawer or bin  35  arranged below oven  20 . More specifically, drawer or bin  35  is adapted to be slid in and out of shell  4  in order to access an interior storage compartment (not shown) therein.  
         [0018]    In the embodiment shown, appliance  2  includes a control panel  50  having arranged thereon a plurality of control elements  53 - 57  which, as will be discussed more fully below, interact with a controller or CPU  58  to set a desired power level for respective ones of heating elements  10 - 13 . Control panel  50  further includes a central display  60  including a digital display portion  65 , a plurality of oven control buttons generally indicated at  67  arranged on one side of central display  60 , a numeric keypad  68  arranged on an opposite side of central display  60 , and a plurality of mode select buttons  69  arranged below digital display  65 .  
         [0019]    Reference will now be made to FIGS. 2 and 3 in describing the specific structure of control elements  53 - 57  arranged on either side of central display  60  of control panel  50 . Since the structure of each control element  53 - 57  is identical, a detailed description of control element  53  will be made and it is to be understood that control elements  54 - 57  have commensurate structure. In the embodiment shown, control element  53  includes a display portion  76  having an upper section  77  and a lower section  78 . In accordance with one preferred embodiment, upper section  77  provides an indication of a selected power level for the associated, in this case, heating element  10  and lower section  78  provides an indication of the time remaining for operating heating element  10  at that particular power level. As shown, extending about display portion  76  is an outer ring  80  having arranged thereon first and second sets of slew buttons  90 ,  91  and  98 ,  99 . In accordance with the most preferred form of the invention, first set of slew buttons  90  and  91  are associated with selecting between establishing a power level and an operating time for that power level respectively. Actually, slew button  90  serves a dual purpose in that slew button  90  also acts as an on/off switch for heating element  10 . Second set of slew buttons  98  and  99  are constituted by up and down arrows respectively which permit a user to increase or decrease the desired power level or time period depending upon the current operating mode of control element  53 . Finally, arranged below control element  53  is an icon  100  which indicates the heating element location associated with operation of the particular control element.  
         [0020]    In accordance with another embodiment of the present invention, the control element can take the form shown indicated generally at  53 ′ in FIG. 4. In a manner similar to that described for the previous embodiment, control element  53 ′ includes a display portion  76 ′ having a power level display section  77 ′ and a time remaining display section  78 ′. In accordance with this form of the invention, control element  53 ′ includes a graphic design  79 ′ which separates power level display section  77 ′ and time remaining display section  78 ′. Extending about display portion  76 ′ is an outer ring  80 ′ having arranged thereon first and second sets of slew buttons  90 ′,  91 ′ and  98 ′,  99 ′. In a manner analogous to that set forth above, slew button  90 ′ and  91 ′ are used to toggle between inputting a desired power level and a desired time period, while slew buttons  98 ′ and  99 ′ are used to increase or decrease the desired power level and/or time period respectively. Finally, an icon  100 ′ is provided at a lower portion of control element  53  to indicate the corresponding heating element associated with operation of the particular control element.  
         [0021]    Having described a preferred construction of cooking appliance  2  and, more particularly control elements  53 - 57 , a preferred method of operation will be set forth with particular reference to FIGS. 1 and 3. In order to commence a cooking operation, a user activates on/off button  90  which causes display  76  to initially display a zero in power level section  77  and a zero in time section  78 . In accordance with one preferred embodiment, initial manipulation of either slew button  98  or  99  causes controller  58  to jump to a particular power level setting, for example 5, which is displayed in power level display section  77 . Further manipulation of slew button  98  or  99  will cause the power level to either increase, i.e., through manipulation of slew button  98 , or decrease, through manipulation of slew button  99 . After reaching a desired initial power level, a pause for a prescribed period, for example 4 seconds, will cause display  76  within time level section  78  to flash. At this time, the user can, if desired, set a time duration for the previously selected power level through the operation of slew button  91 .  
         [0022]    As indicated above, after the selection of the initial power level, the user is presented with the option of setting the time duration for that initial power level. In a manner similar to that previously described, after depressing time pad  91 , the user can either increase, through manipulation of slew button  98 , or decrease, through manipulation of slew button  99 , the amount of time of the initial power level. After the desired time duration has been programmed into controller  58  and after a pause for a predetermined time period, for example 3 seconds, power level display section  77  will begin to flash.  
         [0023]    At this point in the operation, the user is presented with the option of selecting a second or final power level for the associated heating element. In accordance with the most preferred form of the invention, the user has the option of selecting a lower power level such that the final part of the cooking operation will be performed at a lower power setting. Accordingly, manipulation of slew button  99  will lower the power level displayed in section  77  to a desired second level. The option of operating the heating element at a second, higher level is, in the most preferred embodiment of the invention, not available. In further accordance with the invention, failure to select a second power level will cause controller  58  to default to a predetermined lower power level, e.g. a level 1 or 2 setting. If at any point during the cooking operation the user desires to alter the current power setting, manipulation of either slew button  98  or  99  will cause the present power level to increase or decrease correspondingly. Finally, controller  58  will terminate operation of the heating element after a predetermined time period, for example 4-6 hours, if the user either fails or neglects to turn off cooktop  6 .  
         [0024]    With this arrangement, it should be readily apparent that a consumer can pre-set a multi-level cooking operation for each heating element  10 - 14 . That is, a first power level for performing an initial pre-heat process or other high temperature cooking operation is automatically followed by a second lower temperature cooking operation, such as, for example, a simmering process. In this manner, the consumer is able to perform other activities in and out of the kitchen without fear that a pot will boil over onto the cooking surface or the food will boil away leaving behind a charred mess. Although described with reference to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, the particular arrangement of the slew buttons, the overall configuration of the control element, and the display graphics could be readily modified without departing from the scope of the present invention. In addition, control elements for the heating elements could be linked to the oven display to provide the user with a numerical or alpha/numeric indication of the present power setting and time remaining. In general, the invention is only intended to be limited by the scope of the following claims.