Patent Publication Number: US-2018045418-A1

Title: Gas cooktop with defined simmer settings

Description:
FIELD OF THE INVENTION 
     The invention is directed to an apparatus such as a cooktop having defined simmer settings. 
     An example of an application of the invention is a device for setting defined, repeatable knob positions for multiple simmer settings on a gas cooktop in a domestic kitchen. 
     BACKGROUND OF THE INVENTION 
     Domestic appliances, such as gas cooktops that are part of a cooking range or counter mounted gas cooktops, can have multiple heat settings that are input by a user by turning a knob, for example, to a specific position. These positions can include a low position, a high position, and multiple positions in between. The low position is usually the lowest continuous gas flow position. Some gas cooktops also include the ability to set the knob at one or more simmer positions between an off position and the low position. In these simmer positions the gas flow is intermittently turned on and off to achieve a lower average heat setting than the low position. An example of a simmer control is shown in U.S. Pat. No. 5,575,638, the entirety of which is incorporated herein by reference. 
     A problem with simmer controls in existing appliances is that particular knob positions associated with the simmer positions are not defined and are, therefore, not easily repeatable. In such appliances, the knob is simply turned to a position below the low position and an approximate simmer heat level results. If a user wishes to return to a particular simmer level that was previously used, the user is forced to guess as to the position of the knob to achieve that particular simmer level. 
     SUMMARY 
     Exemplary embodiments of the invention overcome the problems in conventional appliances by providing haptics to define positions of the control knob that correspond to defined, and repeatable, simmer settings. 
     Some cooking methods and recipes require very low heating levels. These heating levels can be difficult or impossible to achieve using a constant flame on a gas burner. As a result, embodiments of the invention provide simmer settings of a gas burner that repeatedly switch the flame on and off in a predetermined timing to result in an average heating level that is lower than the lowest achievable heating level that uses a constant flame. These embodiments also provide repeatability in the simmer settings by using, for example, haptics to define a precise location of an input device, such as a control knob, at which a particular simmer setting is achieved. 
     In particular embodiments of the invention, five simmer settings are defined. A lowest simmer setting turns the flame on for ten seconds and off for fifty seconds every minute, another simmer setting turns the flame on for twenty seconds and off for forty seconds every minute, another simmer setting turns the flame on for thirty seconds and off for thirty seconds every minute, another simmer setting turns the flame on forty seconds and off for twenty seconds every minute, and a highest simmer setting turns the flame on for fifty seconds and off for ten seconds every minute. These specific times are just examples, and it is noted that other durations can also be used. Also, having five simmer settings is just an example, and it is noted that a different number of simmer settings can also be used. 
     A particular recipe may call for a very specific simmer setting. Without some form of reliably repeatable simmer setting, such recipes can be very difficult to successfully follow. As a result, embodiments of the invention provide a tactile positioning feature that gives the user an indication that a specific simmer setting is being used. 
     Particular embodiments of the invention include a domestic gas appliance that has a cooktop having a top surface; a user input device; a gas burner located on the top surface; a gas valve fluidly coupled to the gas burner, the gas valve being configured to selectively deliver gas to the gas burner; an igniter configured to selectively ignite the gas delivered to the gas burner; and a control unit that controls a flow of gas through the gas valve and to the gas burner. The control unit has a housing, an urged member attached to the housing, and a rotor attached to the housing and the user input device and having an axis, the rotor being rotatable around the axis to a plurality of positions, the plurality of positions including a number of positions that correspond to a number of simmer settings of the gas valve. The rotor has a main body, and a plurality of engagement features on the main body, each of the engagement features corresponding to one of the simmer settings, the urged member being engaged with one of the engagement features when the rotor is in a position corresponding to one of the simmer settings. Rotation of the rotor requires a first force of rotation to be applied by the user when the rotor is in a position other than one of the simmer settings, rotation of the rotor requires a second force of rotation to be applied by the user when the urged member is engaged with one of the engagement features, and the second force is greater than the first force. 
     Some embodiments include each simmer setting being a repeatable setting in which the gas valve is open for a predetermined open portion of a given minute and in which the gas valve is closed for a predetermined closed portion of the given minute, the sum of the open portion and the closed portion being the entire given minute, and each simmer setting having a different open-to-closed ratio. 
     Some embodiments include all of the simmer settings producing less heat per unit of time than a lowest heat setting where the gas valve is constantly open. 
     Some embodiments include the user input device being a rotatable knob, and the rotor being rotated when rotatable knob is rotated. 
     Some embodiments include the engagement features being indentations on a perimeter of the rotor. 
     Some embodiments include the urged member being a spring actuated plunger. 
     Particular embodiments of the invention include a control unit for use on a domestic gas appliance having a cooktop with a top surface, a user input device, a gas burner located on the top surface, and a gas valve fluidly coupled to the gas burner, the gas valve being configured to selectively deliver gas to the gas burner. The control unit includes a housing, an urged member attached to the housing, and a rotor attached to the housing and having an axis, the rotor being configured to be attached to the user input device, the rotor being rotatable around the axis to a plurality of positions, and the plurality of positions including a number of positions that correspond to a number of simmer settings of the gas valve. The rotor has a main body, and a plurality of engagement features on the main body, each of the engagement features corresponding to one of the simmer settings, the urged member being engaged with one of the engagement features when the rotor is in a position corresponding to one of the simmer settings. The control unit is configured to control a flow of gas through the gas valve and to the gas burner, rotation of the rotor requires a first force of rotation to be applied by the user when the rotor is in a position other than one of the simmer settings, rotation of the rotor requires a second force of rotation to be applied by the user when the urged member is engaged with one of the engagement features, and the second force is greater than the first force. 
     Particular embodiments of the invention include a method of controlling an amount of heat generated by a gas burner on a domestic gas appliance. The method includes controlling with a control unit a flow of gas through a gas valve and to the gas burner by (1) defining a plurality of simmer settings of the gas valve with a corresponding plurality of engagement features on a rotor of the control unit; and (2) engaging an urging member of the control unit with one of the engagement features to select one of the defined simmer settings. Rotation of the rotor requires a first force of rotation to be applied by a user when the rotor is in a position other than one of the simmer settings, rotation of the rotor requires a second force of rotation to be applied by the user when the urged member is engaged with one of the engagement features, and the second force is greater than the first force. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following figures form part of the present specification and are included to further demonstrate certain aspects of the disclosed features and functions, and should not be used to limit or define the disclosed features and functions. Consequently, a more complete understanding of the exemplary embodiments and further features and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an exemplary embodiment of a domestic range having a cooktop; 
         FIG. 2  is a cooktop in accordance with exemplary embodiments of the invention; 
         FIG. 3  is a perspective view of a simmer control unit in accordance with exemplary embodiments of the invention; 
         FIG. 4  is a top view of a simmer control unit in accordance with exemplary embodiments of the invention; 
         FIG. 5  is an exploded perspective view of a simmer control unit in accordance with exemplary embodiments of the invention; 
         FIG. 6  is a top view of a rotor of a simmer control unit in accordance with exemplary embodiments of the invention; 
         FIG. 7  is an edge view of the rotor of  FIG. 6 ; and 
         FIG. 8  is a method in accordance with exemplary embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention is described herein with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
     As explained above, exemplary embodiments of the invention overcome problems in conventional appliances by providing a tactile positioning feature that informs a user when a position of the control knob corresponds to defined, and repeatable, simmer settings. 
     Very low heating levels can be difficult or impossible to achieve using a constant flame on a gas burner. As a result, embodiments of the invention that provide simmer settings of a gas burner that repeatedly switch the flame on and off in a predetermined timing result in an average heating level that is lower than the lowest achievable heating level that uses a constant flame. These embodiments also provide repeatability in the simmer settings by using, for example, haptics to define a precise location of an input device, such as a control knob, at which a particular simmer setting is achieved. 
     A particular recipe may call for a very specific simmer setting. For example, a very low simmer setting can be required when melting specific chocolates or heating specific sauces without burning them. Without some form of reliably repeatable simmer setting, such recipes can be very difficult to successfully follow. As a result, embodiments of the invention provide a tactile positioning feature that gives the user an indication that a specific simmer setting is being used. With embodiments of the invention, a recipe can call for a “simmer 4” setting or a “simmer 2” setting, for example, and the user can rely on the cooktop to provide the specific repeatable heat to successfully complete the recipe. 
     In addition, extremely low simmer settings can be achieved with the invention that cannot be reliably achieved with conventional cooktops. For example, with embodiments of the invention it is possible to melt chocolate on a paper plate without burning the plate. This is achievable because a specific on/off burner ratio with very little burner on time can be reliably set. Such a low heat setting cannot be reliably achieved with conventional cooktops because no tactile feedback is provided to the user. 
       FIG. 1  shows an example of a gas cooking appliance  100  that includes a cooktop  110  that has, in this example, five burners  200 . A control panel  300  includes various controls and displays including, in this example, a corresponding number of control knobs  400  for controlling gas flow to each of the burners  200 .  FIG. 2  shows another example of cooktop  110 . Unlike the example shown in  FIG. 1 , the example shown in  FIG. 2  is a standalone cooktop. The following description applies equally to these two examples, as well as to other cooking devices having a gas burner. 
     Each of the control knobs  400  acts as a user input device through which a user can set the flame level, and the resulting heat level, of its associated burner  200 . Control knob  400  has an off setting that corresponds to no gas flow, a low setting that corresponds to the lowest heat level using a continuous flame, and a high setting that corresponds to the highest heat level. In addition, control knob  400  has one or more simmer settings, each of which corresponds to a setting at which the burner flame is automatically turn on and off according to a defined timing. 
     In particular embodiments of the invention, five simmer settings are defined. Each simmer setting has a defined on/off or open/closed ratio. A lowest simmer setting turns the flame on for ten seconds and off for fifty seconds every minute, another simmer setting turns the flame on for twenty seconds and off for forty seconds every minute, another simmer setting turns the flame on for thirty seconds and off for thirty seconds every minute, another simmer setting turns the flame on forty seconds and off for twenty seconds every minute, and a highest simmer setting turns the flame on for fifty seconds and off for ten seconds every minute. These specific times are just examples, and it is noted that other durations can also be used. Also, having five simmer settings is just an example, and it is noted that a different number of simmer settings can also be used. 
     A control unit is used to send signals to a gas valve and an igniter associated with the corresponding burner  200  in order to control when the flame is on and when it is off according to the selected simmer setting. An example of a control unit  500  is shown in  FIGS. 3-7 .  FIG. 3  shows control unit  500  having a first housing  510  and a second housing  530  sandwiching a circuit board  540 . Circuit board  540  includes various circuits and memory that can store the definitions of the simmer settings and convert (in conjunction with a rotor describe below) the user input, for example rotation of control knob  400 , to electric signals that are sent to various other devices in the appliance. For example, the electric signals can be sent to the burner and igniter that correspond to control unit  500 . 
       FIG. 4  shows an opening  520  in control unit  500  that receives a shaft of control knob  400 . Also shown in  FIG. 4  is a tab  530  that can be used in conjunction with a clip to hold control unit  500  in position. 
       FIG. 5  shows an exploded view of control unit  500 . This view shows a rotor  600  that is located between first housing  510  and circuit board  540 . 
       FIGS. 6 and 7  show rotor  600  in more detail.  FIG. 6  is a top view of rotor  600  and shows a plurality of indentations in the perimeter of rotor  600 . Each of the indentations  610 - 670  corresponds to a particular heat setting of the burner associated with control unit  500 . In this example, indentation  610  corresponds to a setting other than one of the simmer settings. Indentation  610  can correspond, for example, to the off setting, the low setting, or the high setting. The location of indentation  610  is an angle of rotation A from a defined zero. The other indentations are located at other angles of rotation from zero. In this example, indentation  620  corresponds to the lowest simmer setting of control unit  500 , and indentation  670  corresponds to the highest simmer setting of control unit  500 . Indentations  630 - 660  correspond to intermediate simmer settings. For example, indentation  620  can correspond to a simmer setting that turns the flame on for one second and off for nine seconds every ten seconds, indentation  630  can correspond to a simmer setting that turns the flame on for ten seconds and off for fifty seconds every minute, indentation  640  can correspond to a simmer setting that turns the flame on for twenty seconds and off for forty seconds every minute, indentation  650  can correspond to a simmer setting that turns the flame on for thirty seconds and off for thirty seconds every minute, indentation  660  can correspond to a simmer setting that turns the flame on forty seconds and off for twenty seconds every minute, and indentation  670  can correspond to a simmer setting that turns the flame on for fifty seconds and off for ten seconds every minute. 
     An urged member is provided in the housing of control unit  500  for the purpose of engaging the indentations on rotor  600 .  FIG. 5  shows an example of such an urged member in the form of a spring actuated plunger  545 . Plunger  545  rides along the perimeter of rotor  600  as rotor  600  is rotated. When plunger  545  aligns with one of the indentations in rotor  600 , the end of plunger  545  is pressed into the indentation by a spring. When plunger  545  is engaged with one of the indentations, more user-applied force is required to rotate rotor  600  past plunger  545  and, as a result, the user is informed that a defined setting, such as one of the simmer settings, has been selected. 
       FIG. 8  shows an example of a method in accordance with embodiments of the invention. In  FIG. 8 , a plurality of simmer settings are defined at  810 . These definitions are stored in the appliance in, for example, memory in control unit  500 . At  820 , a plurality of indentations are provided on rotor  600 , with each indentation corresponding to one of the simmer settings. At  830 , the control knob is rotated by the user, which in turn rotates rotor  600  to a point where the plunger engages one of the indentations. At  840 , the angular position of rotor  600  dictated by the plunger engaging one of the indentations results in commands for a particular open-to-close ratio being sent to the appropriate devices (such as the burner and igniter) in the appliance such that the chosen simmer setting is achieved. 
     It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the invention.