Patent Description:
Electric waffle makers or waffle irons are well known. A waffle maker generally comprises two heated and hinged together metal plates that are brought together after a waffle batter has been deposited on the lower plate. The two plates or cooking surfaces increase the surface area of the waffle, reduce the cooking time and contribute texture to the finished food article. The mould created by the two plates is open around the edges. The open edges allow excess batter to escape so that the shape of the finished product is preserved.

<CIT> describes a system for determining the status of a food item using time-temperature data. The system includes a lower cooking plate and an upper cooking plate;a temperature sensor configured to provide a temperature signal over time that is indicative of a measured temperature corresponding to a cooking temperature;a processor configured to receive the temperature signal, the processor is configured to control power to the upper and lower cooking plates for controlling the cooking temperature, which causes the cooking temperature to vary within a temperature range over time; and wherein the processor is configured to assign a cooking time that is determined by the respective temperature drop about the time in which food is added to the cooking plate. The system includes a method comprising, sensing a number of temperatures associated with a food item, comparing data related to the sensed temperatures with predetermined temperature data, determining the status of the food item based on the comparison, and causing a predetermined action based on the status of the food item. The method may further involve inputting user information corresponding to the food item, which may include type of food, or the desired level of doneness. The system also includes an apparatus for determining the status of a food item. This apparatus may include means for determining the status of the food item based on the plurality of temperatures, and an indicator for indicating the status of the food item. The determining means may include a microprocessor. The apparatus may further, include a control sensor.

Waffle batters vary in content and cooking characteristics. Further, different users will have differing tastes as to how they prefer their waffles cooked.

Specific teachings are provided in relation to processor controlled I waffle makers and food toasters. However these teachings should be considered relevant to a processor controlled appliance that cook foods in accordance with a nominal or default time that is modified in accordance with one or more user input preferences and one or more properties of the device itself.

As shown in <FIG> a toaster for bread and other food products <NUM> comprises an enclosure <NUM> within which is located a manual or motorised mechanism <NUM> for raising and lowering a carriage <NUM>. The carriage is affixed to a food rack <NUM> for transporting food up and down between an array of heating elements in a toasting cavity that are controlled by, for example, a processor <NUM>. The processor is also adapted to receive information or signals from sensors relating to, for example, the position of the carriage, the temperature in the toasting cavity, various user inputs, toast shade selection, supplemental cycle selection, defrost cycle, selection, food types etc..

These teachings may also be applied to a piazza maker, grill or other cooking appliance.

It is an object of the invention to provide an electrical device according to claim <NUM> that contributes to the ease of cooking a waffle or bread and the ease of cleaning such electrical device.

It is another object of the invention to provide an electrical device giving a user increased control over the cooking process and its outcome.

It is another object of the invention to provide an electrical device having a display that is informative and easy to interpret.

It is another object of the invention to provide an electrical device that is versatile and predictable in its performance.

In order that the invention be better understood, reference is now made to the following drawing figures in which:.

As shown in <FIG>, a waffle maker <NUM> comprises a base or lower housing <NUM> that is connected to an upper housing <NUM> by a pair of hinges <NUM>. The upper housing <NUM> incorporates a forward facing "U" shaped handle <NUM> and upper cover <NUM> and an upper metal cooking plate <NUM>. The base or lower housing <NUM> incorporates a user interface <NUM> having the user inputs or controls <NUM> necessary to operate the unit as well as one or more luminous indicators, multi-colour backlit and an alpha-numeric display <NUM>. The lower housing supports the lower cooking plate <NUM>. The lower plate <NUM> has a circumferential moat <NUM> that forms a continuous channel for receiving batter overflow and spillage.

As shown in <FIG>, the purpose of the upper and lower housings <NUM>, <NUM> is to bring together with upper and lower crenelated plates <NUM>, <NUM>. Each of the plates includes a heating element <NUM>. The power to the heating element is controlled by an MCU, a thermocouple and relay arrangement, microprocessor, fixed or variable thermostat or other control device such as combinations of the aforementioned devices <NUM> (hereinafter "controller'). The controller <NUM> also receives inputs from the user interface <NUM> and drives the display <NUM>. In preferred embodiments, the waffle maker <NUM> also includes a tilt or level sensor <NUM> that supplies information to the MCU <NUM> about the state of the upper housing <NUM>. Because of the heating elements, the level sensor is preferably located within the handle <NUM>. The level sensor or <NUM> switch such as a microswitch is capable of detecting when the upper housing <NUM> is opened or closed and can transmit this information or signal to the MCU <NUM>. The signal may be used to indicate the start of a cooking interval. The position of upper housing <NUM> may also be determined with a mechanical switch or sensor <NUM> located in the lower housing or a switch or sensor <NUM> located in the upper housing. The switch or sensor <NUM>, provide a signal to the MCU that indicates when the upper housing is opened or closed. The MCU then causes the entire display to change from one colour to another when the waffle maker <NUM> is operational and closed. The information may also be used to start the timer or count-down timer.

The lower plate <NUM> incorporates an integral, peripheral moat <NUM>. In preferred embodiments, the moat <NUM> is continuous and formed adjacent to the outer rim of the lower plate where the upper and lower plates come together <NUM>. When pouring or heating waffle batter, excess will flow over the rim <NUM> and into the moat <NUM>. When compared with other waffle makers, the moat depicted in <FIG> is large, having a volume ratio (when compared to the batter volume of a waffle) of <NUM>:<NUM> or more, with a lower practical limit of about <NUM>:<NUM>. In preferred embodiments, the internal radius <NUM> of the moat <NUM> is at least <NUM> and up to <NUM> or larger. The preferred shape of the moat is essentially or approximately a section of a circle.

As shown in <FIG>, the upper and lower plates <NUM>, <NUM> are capable of forming a cavity <NUM>. The cavity <NUM> has edges. The cavity edge of the lower plate <NUM> is formed by a short horizontal shoulder <NUM> located between the cavity <NUM> and the moat <NUM>. Batter that escapes over the edge <NUM> is captured in the moat <NUM>. Note that the size and shape of the moat <NUM> are such as to conform to the size and shape of an adult human finger <NUM>. This assists with cleaning spilt batter from the moat both during and after cooking has occurred and the unit has cooled. The cavity edge of the upper plate <NUM> is formed by a downward facing rectangular rim or bead <NUM> formed on a horizontal surface <NUM> around the periphery of the upper plate <NUM>. The bead may be on the lower plate and upward facing. The continuous peripheral bead <NUM> serves to increase the contact pressure between the two respective edges. This serves to better separate the interior of the cavity <NUM> from any batter that is located in the area of the edge <NUM> or outside of it. The upper plate <NUM> has a peripheral and upstanding rim <NUM> that is preferably located above the bead <NUM>.

<FIG> illustrates, in perspective view, the waffle maker <NUM> with the top cover <NUM> removed. This view illustrates the double interconnected "U" shaped path for the upper heating element <NUM> that is created by a raised channel <NUM>. The channel is cast into the back face of the upper plate <NUM>. The channel is continuous and having, for example, four approximately equally spaced limbs <NUM>, <NUM>, <NUM> and <NUM>. The open ends of the channel <NUM> face the rear of the upper plate. The open ends <NUM> are found on the two inner limbs <NUM>, <NUM>. The outer limbs <NUM>, <NUM> connect to one another behind the open ends <NUM> (with reference to the rear of the waffle maker; see <FIG>). The channel <NUM> has integral ribs <NUM> that radiate away from it, particularly in the areas of the rounded corners <NUM> that join the various segments of the channel. These integral ribs <NUM> assist in transferring heat from the heating element and its channel to the more remote regions of the lower plate so as to achieve a more uniform heating.

<FIG> also illustrates the construction of the parallel hinges <NUM> that interconnect the upper and lower housings. Each of the lower hinge elements <NUM> is moulded into the lower plate <NUM>, outside of or behind the periphery of the moat <NUM>. A hinge pin <NUM> joins each of the lower hinge elements <NUM> to an upper hinge element <NUM>. The pivot or pin <NUM> is preferably located above the level of the moat to prevent being fouled by batter. The two elongated upper hinge elements <NUM> are interconnected by a transverse rigidising "L" shaped bracket <NUM> or formed as a single unit. Further details of the hinge arrangement are depicted in <FIG>.

As shown in <FIG> and upper hinge element <NUM> has a rear end <NUM> in which is formed a hinging area, being in this example an opening <NUM> for the hinge pin <NUM>. The forward end <NUM> of the hinge element <NUM> comprises a downward extending finger <NUM>. As suggested by <FIG>, when the upper and lower plates are brought together in a fully closed orientation, a lower and preferably flat end of the finger <NUM> makes contact with the interior and upper surface <NUM> of the upper plate <NUM> (being a part of the upper housing). An intermediate hinge point <NUM> is formed on the upper hinge element between the rear end <NUM> and the finger <NUM>. In this example, the intermediate hinge point <NUM> comprises of an opening that surrounds a transverse shaft <NUM> that is supported above and retained by a saddle to the upper surface <NUM> of the upper cooking plate <NUM>. Thus, the upper hinge elements <NUM> pivot in two locations. At a first location <NUM> or rear pivot, the upper hinge element <NUM> pivots with respect to the lower housing. At a second or intermediate location or area <NUM> the hinge element pivots with respect to the upper housing. Because of this geometry, the upper housing "floats" or can be displaced upwardly in a way that is essentially parallel with respect to the lower housing of base. This is depicted in <FIG>. Displacement of this kind occurs, for example, as the batter is heated and expands. The pressure between the upper and lower plates is essentially uniform and overflow <NUM> escapes the gap between the two plates and enters the moat. As illustrated in <FIG> when the front handle <NUM> is used to open or pivot the upper housing, the upper surface <NUM> of the upper plate <NUM> contacts the lower end of the finger <NUM>. This limits the inclination or movement of the upper housing with respect to the upper hinge element. Thereafter pivoting can only occur at the rear most hinge point <NUM> as the unit is opened.

As shown in <FIG>, the extent of the parallel separation between the two plates caused by the expanding batter (see <FIG> may be limited. As suggested by <FIG> a contact bumper <NUM> may be formed above the upper surface <NUM> of the upper plate <NUM> in an area rearward of the intermediate hinge point or hinge area <NUM>. Note that in <FIG> there is a small gap <NUM> between the upper tip of the bumper <NUM> and the lower surface of the hinge element <NUM>. The gap <NUM> is at its maximum when the two plates are brought together and in contact with one another. In effect the gap <NUM> between empty upper and lower plates is zero. As shown in <FIG>, as the upper and lower plates move apart from one another, the gap <NUM> between the bumper and the upper hinge element <NUM> is reduced until the bumper <NUM> actually contacts the underside of the hinge element <NUM>. Thus the gap <NUM> is reduced to zero as the plate gap <NUM> reaches its maximum. Further upward movement of the upper plate is then hindered.

A more detailed view of the upper hinge element <NUM> is shown in <FIG>. The hinge element <NUM> comprises a unitary limb having a rear pivot location <NUM> and an intermediate pivot location or area <NUM> as previously discussed. An "L" shaped bracket <NUM> interconnects the left right hinge elements <NUM>. In preferred embodiments, the shorter and upwardly directed edge <NUM> of the bracket <NUM> rests within a gap that is located between the downward extending finger <NUM> and a flat forward facing surface <NUM> of the hinge element body. The intermediate hinge point or opening <NUM> is formed in a lobe <NUM> that extends from the underside <NUM> of the hinge element body.

As shown in <FIG>, storing and transporting the waffle maker <NUM> is facilitated by a pivoting mechanical lock that selectively connects the upper housings handle <NUM> to an outside edge <NUM> of the overflow moat <NUM>. As suggested by <FIG>, by way of example, an outside surface <NUM> of one or the handle's side pieces <NUM> may contain a pocket of cavity <NUM> for receiving a bi-stable pivoting clip or lock <NUM>. The lock is attached to the handle by a central pivot point <NUM> and moves from a concealed orientation depicted in <FIG> to an extended orientation as shown in <FIG>. In the extended orientation, the hook-like body of the lock is adapted to engage below or with an overhang or rim 806a that surrounds at least that part of the moat that lies below the handle <NUM>. The edge <NUM> of the moat lies within a recess <NUM> in the lock body. In this way, no part of the lock body <NUM> enters the moat <NUM> or interferes with it. The pivoting lock body <NUM> is stable in both of the positions illustrated in <FIG>. This is accomplished by using a resilient wire spring shaped in the manner depicted in <FIG>. The spring <NUM> is stable in those two orientations but can to bias the lock body into the retracted orientation depicted in <FIG> once dislodged from the locked orientation. The spring comprises a first free end <NUM> that is inserted into an opening <NUM> in the lock body. The spring has a central loop <NUM> for added resiliency and a terminal loop <NUM> for affixation.

As shown in <FIG> a pivoting mechanical lock that functions similarly to the one discussed with reference to <FIG> may utilise a leaf-spring <NUM> instead of a resilient wire spring. Both the leaf-spring <NUM> and the pivoting lock body <NUM> are concealed within one of the pair of side pieces <NUM> that are used to support the cross bar <NUM> of the device's handle <NUM> in this example, a leaf type spring <NUM> is deflected by the rounded corner <NUM> of the pivoting lock body and has two stable positions. One position conceals the rotating lock body within a recess <NUM> in the side piece and the other orientation locates the lock body <NUM> in an extended position in which it protrudes from the recess <NUM> and is adapted to engage either an edge of the lower cooking plate or a portion on or associated with the lower housing.

As shown in <FIG>, the side pieces <NUM> of the handle <NUM> may have a pocket for concealing the pivoting, retractable lock body <NUM>. In preferred embodiments, the lock body <NUM> further comprises a lateral extension <NUM> on which may be printed or affixed a warning 904a. The nature of the warning is that the lock should not be engaged with the base or lower housing when waffles are being cooked. The lock is intended for compactness and stability during storage or transportation. The lateral extension <NUM> may be received within a second pocket <NUM> that is interconnected with the first pocket <NUM> that receives the lock body. The preferably flat exterior or visible surface <NUM> faces downward or away from the user when the lock body is concealed. However, as shown in <FIG> the warning label or indicator 904a faces forward and thus can be seen by the user when the lock body is in its extended position.

The user interface <NUM> is depicted in <FIG>. The user inputs include a control with a luminous indicator ring <NUM> for restarting the timer <NUM> and the time display <NUM>, a button or control for initiating a single, fixed increment of additional cooking time (for example <NUM> seconds) <NUM>, a button or other control <NUM> for initiating manual override of the automatic aspects of the cooking process, a rotating dial <NUM> for simultaneously selecting cooking temperature and time and an adjustment knob or dial <NUM> for varying the pre-established cooking time of a waffle. While the temperature selector <NUM> is depicted as a rotating knob, it will be understood that it could also be a slide or other control element that provides either continuous or discreet control. The interface <NUM> further includes an alpha-numeric display <NUM>. The display <NUM> has selectively displayable portions to provide information to the user. The display also changes colour (e.g. white to red) when the upper housing is closed. A first portion <NUM> selectively alerts the user to close the lid or upper housing to start the count down timer that displays the remaining time in a cooking time or interval. The first portion <NUM> is not visible during a cooking cycle. Signals from the level or tilt or other sensors or switches (<NUM>, <NUM>) allow the MCU to determine when the lid is closed. A second segment <NUM> displays one of, for example, five discreet descriptors that correspond with the time setting or a combination of temperature and time in some embodiments. In the numbered list shown in the example of <FIG>, five different batters are individually listable in the display. In this example, "<NUM>. CHOC/FRUIT" indicates the lowest selectable cooking temperature and is used for those batters that generally have the highest sugar content. The remaining four sub-segments of the display contain descriptors that correspond with the other four temperature settings on the temperature adjustment dial <NUM>. The controller will establish a cooking time that may be inversely proportional to the cooking temperature or not. A third segment <NUM> illustrates a "sliding scale" with the word "light" at one end and the word "dark" at the other end. Individual arrow segments <NUM> illuminate to show the degree of lightness or darkness either as set by the controller or selected by the user as a result of utilising the time/colour control knob <NUM>. Each of the individual arrows <NUM> corresponds to a position of the time time/colour control knob <NUM>. A fourth segment <NUM> contains numeric segments that can display the time remaining associated with any cooking operation. A further segment of the display is adapted to display either "add batter" <NUM> (when the desired cooking temperature has been reached but the lid or upper housing is open) or "pre-heating" <NUM> before the actual cooking temperature has been reached.

<FIG> illustrates an underside of the lower cooking plate <NUM> as well as a printed circuit board (PCB) <NUM> to which the electro-mechanical components of the user interface are attached. In effect, the temperature adjustment knob <NUM> is the primary user control and is preferably the physically largest user operable control on the interface. The knob <NUM> is mounted to a front surface of the PCB <NUM>. The knob has a shaft which passes through the PCB <NUM> and is associated with a potentiometer <NUM>. The potentiometer <NUM> sends a signal to the device's MCU that is interpreted as the user's selection of temperature level. This information is used by the MCU to calculate the countdown time associated with the selected temperature. The knob's shaft <NUM> has a transverse through hole or is otherwise attached to a coupling component having a transverse through hole (or the like) that allows the control knob <NUM> to also act on a thermostat shaft <NUM> as will be better explained with reference to <FIG>.

With reference to <FIG> and <FIG> it can be seen that a mechanical linkage <NUM> interconnects the knob shaft <NUM> with the thermostat's shaft <NUM>. The linkage facilitates the assembly of these remote parts. The thermostat shaft <NUM> rotates a thermostat gear <NUM>. The thermostat itself (as shown in <FIG>) is affixed to an underside of the lower plate and is therefore in intimate thermal contact with the lower plate. The thermostat provides temperature information to the micro controller. The primary knob <NUM> is also associated with an on-off switch <NUM> so that the primary knob <NUM> can be used to switch the waffle maker <NUM> on or off.

The main control knob <NUM> provides approximately <NUM> degrees (or time or combined temperature and time) of rotation, preferably encompassing five discreet temperature settings separated by approximately <NUM> degrees of rotation. In one embodiment the setting relates to an order of decreasing sugar content, the five settings being (as found on the alpha-numeric display) CHOC/FRUIT, CLASSIC, EGG WHITE, BUTTERMILK and SAVOURY. These designations are displayed, one at a time as the knob is rotated from the lowest temperature to the highest. The designations are displayed for a limited time (e.g. <NUM> seconds) every time the main knob <NUM> is adjusted. After that only the selected designation is displayed.

Each arrow segment <NUM> on the display is associated with e.g. <NUM> seconds of time deviation from the nominal pre-established setting established by the main knob <NUM> in conjunction with the MCU. If the scale is already at a maximum darkness and the user adds more time, the arrow will blink. The time/colour adjustment adjusts the recommended cooking time by plus or minus <NUM> seconds for each stop on the encoding knob. Each arrow segment <NUM> corresponds to <NUM> seconds of adjustment. If the time is adjusted during the cooking cycle, the micro processor's memory remembers the amount of time difference for the next cycle. The new adjusted count-down time is displayed dynamically. If the main control knob position changes, the MCU's memory remembers the time and darkness setting. If a new setting is selected on the main knob <NUM>, the user adjustment from the time/colour setting <NUM> is added to the newly selected time by controller. The "A Bit More"™ button adds a fixed or user selected time, e.g. <NUM> seconds to the timer each time it is pressed. The "ADD BATTER" prompt or warning is only displayed once during a waffle making session. It is displayed from the first time the thermostat shuts the heating element off until the first time cycle begins. The "PRE-HEATING" notification is only displayed the first heating cycle and preferably, it flashes. Thereafter, only "heating" is displayed and it is displayed on every thermostat heating cycle.

The "Manual Control" button or input <NUM> toggles between a "smart" mode and a "manual" mode. The smart mode is the default setting. In the smart mode, batter types are displayed <NUM> and the darkness or colour or shade scale <NUM> is displayed. In the manual mode, batter types are not displayed and the light/dark scale is not visible. The clock segment of the display is visible and the "manual" button back light is on.

In one particular embodiment of the technology, a thermostat <NUM> is used to monitor the temperature of the lower plate <NUM> and to switch the delivery of power to the heating elements in accordance with the sensed or indicated temperature. It is preferred that the thermostat <NUM> be located centrally and below the lower plate <NUM> and in intimate contact with the lower plate the thermostat <NUM> may be a fixed thermostat or a variable thermostat. The switching state of the thermostat <NUM> is provided to the device's MCU <NUM>. The MCU <NUM> stores information relating to the state of the thermostat's contacts over time. The MCU <NUM> also detects and optionally stores a more accurate record of the temperature of the plates as provided by the signal from an NTC thermistor <NUM> that is in intimate contact with the lower plate. In preferred embodiments, the thermistor <NUM> is located either centrally under a particular waffle cavity <NUM> or centrally with regard to the lower plate <NUM>. As suggested by <FIG>, the relatively low cost and robust thermostat <NUM> may be replaced by a centrally located NTC thermistor <NUM>. The thermistor <NUM> provides temperature information to the MCU <NUM>. The MCU <NUM> communicates with a switching relay <NUM> that switches the power delivered to the heating element or elements <NUM>. The switching state of the relay <NUM> is monitored by the MCU <NUM>. Information regarding the temperature of the plates and the switching state of the thermostat or relay is used to provide information to the user, via the display <NUM> regarding an optimum time to add batter, when to close the plates together and when the waffle is cooked. This information is also used in the calculation of the correct cooking time as will be explained.

As shown in <FIG>, and as preferably measured by the MCU and the NTC thermistor <NUM>, the measured temperature of the cooking plates changes over time. When the heating elements are first switched on <NUM>, the elements are at a nominal or ambient starting temperature. The delivery of power to the elements causes a rise in the temperature of the plate <NUM>. Because the plates have thermal inertia owing to their mass and composition, an optimum or nominal cooking temperature <NUM> will be exceeded after the elements are switched off at the optimum cooking temperature <NUM>. The temperature will reach a maximum referred to as the over-shoot temperature <NUM>. This can potentially serve as a point in time from which the processor will indicate via the display that pre-heating is finished and that batter may be added. Because power is no longer being supplied to the heating elements, the plates will cool <NUM> thus, the plate's nominal cooking temperature is reached at a point in time <NUM> when the heating elements are off. The point in time <NUM> when the heating elements are on and the temperature of the plates begins to rise again constitutes another point in time when the MCU may deliver an instruction to the user, via the display <NUM> that it is time to "add batter" (see <NUM> in <FIG>). In some embodiments the "add batter" time may be delayed after a salient event. It will be appreciated that the measured temperature of the cooking plates will vary over time as the elements are switched on and off. Further, the precise moment in time in which the user adds batter cannot be either pre-determine or predicted by the MCU. Accordingly, in one embodiment, the MCU registers the drop in temperature from the output of the thermistor <NUM> and uses that drop in temperature (by a predetermined amount) to indicate a moment in time when the batter has been added. Because the optimum or nominal cooking time will vary in accordance with the point in time in which the batter is added, the MCU assigns different cooking times (in this embodiment) in accordance with when batter is added. It will be understood that cooking time may refer to a time that is indicated or suggested to a user by a counter, timer or other indicator, or to a time after which cooking is terminated for example, by the switching off of a heating element or the ejection of a food like toast.

In the example of <FIG>, the measured temperature profile over time <NUM> is subdivided by the microprocessor into a number of manageable temperature bands <NUM>. In this example, each band represents a temperature range of approximately <NUM> degrees centragrade starting from about <NUM> degrees centragrade through to <NUM> degrees centragrade. Potential cooking time values are represented by time zones X1-X12 <NUM>. Zones are preferably assigned, in the equal number (in this example <NUM>) within each temperature fluctuation cycle <NUM> being an equal number (<NUM>) between the temperature maximum <NUM> and the temperature minimums <NUM>, <NUM> that the defined a beginning and end of a particular temperature fluctuation cycle <NUM>. It will be appreciated that the number of bands <NUM> and the number of zones <NUM> may deviate from the values provided by this example. The optimum cooking time will vary, depending upon whether or not the temperature of the plates is rising because the heating elements are switched on or falling because elements have been switched off. Accordingly, per <FIG> zone X1 represents a shortest actual cooking time and that cooking time and the other times are stored in a memory accessible to the MCU at the time of manufacture. Similarly, (per <FIG>) if batter is added in the time zone X6, the cooking time will be the longest for a particular batter type. This is because the elements have been switched off after a temperature maximum <NUM> has been reached. Thus, the MCU can identify a time zone X1-X12 in accordance with a sensed or measured drop in cooking plate temperature and the time that the drop occurred with reference either the temperature maximums and minimums or to the elements having been switched on <NUM> or switched off <NUM>.

As shown in <FIG>, a variable thermostat has at least <NUM> temperatures <NUM>, <NUM> that may be selected by a user. The measured temperature of the waffle maker's plates varies for each selected temperature in the way depicted in <FIG>. In a similar way, a temperature fluctuation cycle is subdivided into discreet time zones <NUM>, <NUM> in accordance with pre-established temperature bands <NUM>. However, for each pre-selected temperature <NUM>, <NUM> the cooking time values associated with each zone <NUM>, <NUM> are different. The MCU uses a look-up table containing the cooking time values associated with each zone to determine the cooking time for a particular batter at the selected temperature <NUM> or <NUM>.

As shown in <FIG>, a look-up table of cooking time values comprises an array of stored values comprising fixed, individual pre-established suggested cooking times <NUM> associated with each time zone <NUM>. In this example, the array comprises values for four different kinds of waffle batter <NUM>, <NUM>, <NUM>, <NUM>, each batter type having <NUM> discreet time zones based on <NUM> temperature bands <NUM> comprising <NUM> bands that occur after a temperature minimum and <NUM> bands that occur after a temperature maximum <NUM>. A first type of batter <NUM> is a Belgium waffle type. Other batter types may have factors such as a different sugar content or the presence of other ingredients that causes that batter type to have a different cooking time that the Belgium waffle batter type <NUM>. It will be appreciated that the time that is stored and therefore used by the MCU in respect of a particular zone may be varied by the user using the time/colour input or control <NUM> (see <FIG>).

In summary, one method of operation of the unit accounts for the initial pre-heating of the plates and the over-shoot of the nominal or cooking temperature. A user is provided with an indication after the first time that the heating elements have been turned off that the optimum pre-established cooking temperature has been reached for the first time. This indication provides the user with information in that it is appropriate to add batter. A temperature measuring device such as a thrermistor than continuously measures the temperature of the cooking plates sends a signal to a MCU than indicates a drop in temperature of the cooking plates caused by the addition of batter. The point in time at which the batter is added is correlated with a temperature band in which it occurs. The band relates to the temperature as well as the switching state of the thermostat or relays that controls power to the heating elements. The results and value identifies a single time zone. Each time zone is associated with a pre-stored cooking time. A range of zone related cooking times is pre-stored for each selectable batter type. A user is able to adjust the pre-established time to either add or subtract time. The pre-established time and a countdown timer are displayed for the user's benefit. Alteration of the pre-established time results in an apparent movement of an indicator on the display. A graphic representation of the time remaining is also adjusted in accordance with the user's selection. At the end of the pre-established or user altered cooking time, the user is provided with an indication on the display. This signals the user to open the waffle maker and remove the cooked waffle even though the elements continue to operate. At any point during a cooking cycle or between cooking cycles, the user can select, using a single input such as a button, an additional increment of time that is added to the pre-established or user altered cooking time. This results in an alteration of the graphic representation of countdown time and the graphic indication of the lightness or darkness of the waffle.

In other embodiments the cooking time or information relating to the cooking time, such as the display of a count-down time, is based on when the upper housing is closed, as sensed by the level sensors located for example, in the upper housing. In embodiments of this type, the user is not provided with a prompt for when to add the waffle batter. However, recommended cooking times and subsequently a count-down of same are displayed on the user interface of the waffle maker and are based on the measured or detected cooking surface temperature as determined by a sensor such as an NTC thermistor <NUM>, a selection made by the user based on batter type, and optional lightness-darkness (time) adjustment that can be made by a user, an addition of a supplemental time interval being either a fixed or variable interval <NUM> and optionally, the state of a thermostat associated with one of the cooking plates. An embodiment of this type is disclosed with reference to <FIG>.

As shown in <FIG>, the temperature <NUM> of the plates or cooking surfaces will vary over time in accordance with the state of the thermostat (e.g. <NUM>). The thermostat is considered "on" when its contacts are closed and power is being supplied to the heating elements. Conversely, the thermostat is considered "off" when the contacts are open. Consequently, the state of the thermostat will cycle between "on" states <NUM> and "off" states <NUM> while the device is in use. Adding batter to the lower plate at a point in time <NUM> when the thermostat is off will cause a relatively fast decrease in temperature <NUM> and may cause the actual temperature of the cooking surface to fall below the thermostat's nominal lower temperature limit <NUM> for a specific temperature band. As shown in <FIG>, adding batter when the thermostat is on <NUM> causes only a modest decrease <NUM> in the temperature of the cooking surfaces. For these reasons, batter that is added when the thermostat is off <NUM> requires a longer cooking time than batter that is added <NUM> when the thermostat is on.

A waffle maker made in accordance with the teachings of the invention can accommodate these differences in cooking time by detecting both the plate temperature and the state of the thermostat as suggested by <FIG>. In embodiments of this type, the device's MCU consults and utilises a time value from a look-up table that has been populated with cooking times, the look-up being based on the measured plate temperature and the state of the thermostat, this information also being provided to the MCU. In the example of <FIG>, the range of possible plate temperatures <NUM> is subdivided into six (<NUM>) bands <NUM>. There may be more, or fewer bands. In this example, the lowest band represents the range of temperatures below 139C. The second band <NUM> represents temperatures between <NUM>-159C. The third band <NUM> represents temperatures between <NUM>-179C. The fourth band <NUM> represents temperatures between <NUM>-199C. The fifth band <NUM> represents temperatures between <NUM>-219C. The sixth band <NUM> represents temperatures at or above 220C. For each temperature band, there are time values for a thermostat "on" state <NUM> and a thermostat "off' state <NUM>. For each temperature band and thermostat state combination, there are four possible cooking times <NUM> because cooking time data has been stored in a look-up table for use by the MCU for four (<NUM>) different batter types <NUM>. In order to determine a nominal or default cooking time, the MCU reads the plate temperature sensed by the NTC thermistor at the time when the upper housing is closed or for example, when a significant or rapid temperature drop is detected by a sensor such as the thermistor. This is detected by a tilt switch or mechanical switch or proximity sensor as previously disclosed. In one example, the MCU determines that the plate temperature is 220C when the upper housing is closed. This places the determined temperature in band six, <NUM>. For the purpose of this example it would be assumed that the MCU also detects the thermostat state as "on". Thus based on the aforementioned measurements and the selection of a batter type corresponding to a Belgium waffle <NUM> the MCU will perform a look-up operation of the nominal or default cooking time in a register or memory location designated symbolically in <FIG> as "T21" <NUM>.

As shown in <FIG>, the cooking process may be somewhat simplified by utilising a more thermally stable or thermally inert cooking surface, one whose temperature does not vary significantly between thermostat "on" and thermostat "off" states. The unit may also operate without reference to thermostat by for example, utilising a nominal or default cooking time that is effective in either the "on" or "off" state of the thermostat. Thus, and as shown in <FIG>, the look-up operation performed by the MCU, being in this example "T18" <NUM> is based solely on the batter type (in this example, "CLASSIC" <NUM>) and the sensed plate temperature (in this example, 210C) <NUM>.

As shown in <FIG>, a user interface <NUM> for operating a waffle making device fabricated in accordance with the previous examples comprises a graphic display <NUM>. The display includes alphanumeric segments <NUM> that may be used to provide a countdown of the suggested cooking time and a further indication such as the word "end" when the countdown has reached zero. The heating elements are not turned off at the end of the count down. The display <NUM> may also include an indication such as individual segments in a linear array <NUM> that are indicative of the light-dark adjustment setting made by the user. In this example, the light-dark adjustment is made with a rotating knob <NUM> having twelve (<NUM>) discreet settings. Each setting is represented by one segment in the array <NUM>. In some embodiments, the array <NUM> can also serve as a countdown whereby the recommended cooking time is subdivided by the number of segments that are activated or illuminated, one segment being extinguished upon the elapsing of one said time interval, until no segments are activated or illuminated and the suggested cooking time has elapsed. The display <NUM> may also contain a list of cooking modes <NUM>. In this example, there are four (<NUM>) modes corresponding to four (<NUM>) different batter types in order of sugar content, being: BELGIUM, CLASSIC, CHOCOLATE and BUTTERMILK. A fifth mode or item in the list <NUM> correspond to a "custom" cooking mode in which the operation of the device is entirely manual.

Recipes for the aforementioned waffle types is provided below.

The user selection of a mode in the list <NUM> is made using a rotating knob <NUM>, or a slider of push buttons. In this example, the knob has discreet click-stops, one stop corresponding to each item in the list <NUM>. The interface also features a restart button <NUM> for restarting the timer and an "a bit more" button <NUM> for adding either a fixed or user variable time interval to the suggested time interval as determined by the device's MCU.

<FIG> and <FIG> and the related portions of this specification disclose a method whereby a processor or MCU in a waffle maker can determine a nominal or default cooking time <NUM>, <NUM>, <NUM>. In addition, the MCU or processor can use the nominal or default cooking time and optionally modify it to produce a resultant or actual cooking time based on additional factors. For example, the MCU can use the detected temperature drop, as measured by the NTC thermistor, when batter is added to determine if and how much additional cooking time is required. Further, the MCU can add additional time based on the single input "A Bit More" user control button <NUM>, <NUM> as previously disclosed. The MCU can also modify the nominal or default cooking time in accordance with a lightness-darkness selection resulting for the user input. As discussed with reference to <FIG>, the user interface may have a lightness-darkness adjustment input such as a knob <NUM>. In the example of <FIG>, there are <NUM> discreet settings available the knob <NUM>. As suggested by <FIG>, the lightness-darkness setting can result in the additional or subtraction of time, from the nominal or default cooking time, to result in actual cooking time. In any event, it is preferred that the actual cooking time (based on the nominal or default cooking time compensated by other factors) be displayed after the upper housing is closed. The actual cooking time that is displayed is then used as a basis for the display of a countdown which when finished, is a prompt for the user to open the upper housing and remove the cooked waffle. In the examples depicted in <FIG>, and for each waffle type and thermostat state, there are four cooking bands. Each band is associated with twelve bars, corresponding to the twelve settings on the user input <NUM>. If there is no additional user input, the lightness-darkness default setting is represented by the value "<NUM>" in each of the temperature bands depicted in <FIG>. For example, in <FIG>, in the lowest band <NUM> the nominal or default suggested cooking time (corresponding to six bars) is <NUM> seconds. The micro processor determines the time values for each of the other lightness-darkness settings by dividing the nominal or default cooking time (<NUM> seconds) by six. In this example, the resulting increment is <NUM> seconds. This value represents at least the approximate incremental difference between adjacent settings or "bars" in the lightness-darkness setting knob <NUM> and in the corresponding display <NUM>. With reference to the lowest setting, it may be determined by subtracting <NUM> seconds from the second to lowest setting. This has been empirically determined based on the particular plates, heating element.

<FIG> represent schematically, a look-up table corresponding to a user selection of a Belgium waffle type where the upper housing is closed when the thermostat is in an "on" state. In this example, the entire range of plate temperatures has been subdivided into four (<NUM>) bands <NUM> and each band is associated with twelve (<NUM>) optional lightness-darkness settings that are user selectable <NUM>. For each lightness-darkness setting in each temperature band there is a time value <NUM> stored and accessible to the MCU. In this example, the time value associated with a lightness-darkness setting of six (<NUM>) represents the default cooking time in each temperature band. In the temperature band corresponding to a determined plate temperature of 159C or less, the default cooking time is <NUM> second. This corresponds to an alphanumeric display on the graphic display <NUM> of <NUM>:<NUM><NUM>. In this example, the increment between different lightness-darkness settings is determined by dividing the default cooking time by six (<NUM>). As previously mentioned, each upward or downward adjustment from the nominal or default value of six (<NUM>) represents a time interval of <NUM> seconds. In this particular example, the interval between the two (<NUM>) lowest darknesslightness settings is determined by subtracting ten (<NUM>) seconds form the second lowest value. Accordingly, the second time value in the lowest temperature band is <NUM> seconds and the time value for the lowest darknesslightness setting is <NUM> seconds. <FIG> provides data for the time look-up values associated with a Belgium waffle selection made by the user when batter is added while the thermostat state is "off". A comparison of the cooking times in <FIG> and <FIG> will reveal that the cooking times are uniformly longer when batter is added in the thermostat "off" state.

<FIG> provides examples of cooking times determinable by the MCU from a look-up table for a "Classic" batter type that is added when the thermostat state is "on". <FIG> provides corresponding data for when batter is added while the thermostat state is "off".

<FIG> provides examples of cooking times determinable by the MCU from a look-up table for a "Buttermilk" batter type that is added when the thermostat state is "on". <FIG> provides corresponding data for when batter is added while the thermostat state is "off".

<FIG> provides examples of cooking times determinable by the MCU from a look-up table for a "Chocolate" batter type that is added when the thermostat state is "on". <FIG> provides corresponding data for when batter is added while the thermostat state is "off".

The aforementioned disclosure pertains to a waffle maker that calculates a nominal or default cooking time in accordance with a first user action (being a closing of the upper housing), a measured plate or cooking surface temperature, an optional consideration of a thermostat state, a user input relating to a batter type, and optional parameters such as a user input regarding a desired lightness or darkness or the addition of a fixed or variable additional time by way of a single button input.

The toaster of <FIG> may have a user interface as depicted in <FIG>. The user interface may consist of components such as a graphic display <NUM>, in this example, the graphic display <NUM> contains a graphic list of food or bread types <NUM>. In this example, each item in the list <NUM> is associated with a "moving" indicator <NUM> which may be activated or illuminated so as to indicate a selection made by a user. The user's selection of bread or food type <NUM> may be accomplished with, for example, a rotating knob <NUM>. Rotation of the knob <NUM> communicates information to the processor which indicates the selection and causes the processor to change which item in the list <NUM> is associated with the indicator <NUM>. Each bread or food type in the list <NUM> is associated with a default or nominal cooking time stored in a register or memory location of a look-up table that the processor can read <NUM>. In some embodiments, the default or nominal toasting or cooking time is indicated in an alphanumeric display <NUM>. However, the initial, default or nominal toasting time may be altered in accordance with one or more user inputs to result in an actual toasting time. In one example, the exterior of the toaster features a slide type user control <NUM> or another rotating selector knob similar to the food type selector <NUM>. The food type selector <NUM> may be used for both purposes when a toggle switch is provided. In preferred embodiments, the slider or other user control <NUM> allows the user to select from a discreet number of settings, each setting having the effect of either decreasing or increasing the default or nominal toasting time. This increase or decrease in the nominal or default toasting time is referred to as adjustment over toast lightness or darkness. The extent of lightness or darkness requested by the user using the control <NUM> is represented in the graphic display <NUM> by an array of discreet segments <NUM>. In this example, the range of cooking times selectable by the user and including the default time is represented by ten (<NUM>) discreet segments. The extent to which the array is activated or illuminates indicates the user selection from the control <NUM>. The aforementioned look-up table can be provided with calculated, algorithmic or empirically determined times representing the increment up or down from the nominal or default time in accordance with the selection from the control <NUM>. When a user selection is made using the control <NUM>, the resulting or actual cooking time is then displayed by the alphanumeric segments <NUM>. Further adjustment to the actual cooking time may be accomplished with a single push button input <NUM> that adds a fixed or user selectable increment to the previously determined cooking time. This is similar to the user control <NUM> described previously. A further form of user modification of the initial cooking time is a push button or other user input for selecting a supplementing of the aforementioned cooking times by an additional increment when the defrosting of a frozen or partially frozen food item is required. The amount of defrosting may vary in accordance with different items in the list <NUM>. A single or individually selected defrost time increments may be contained in the look-up table for the use by the processor <NUM>. In this example, the toaster works by the user making selections represented by the various inputs <NUM>, <NUM>, <NUM>, <NUM>, <NUM> then pressing a start/stop button or user input <NUM>. The toasting or cooking operation will continue until the actual cooking time elapses whereupon the toast rack <NUM> will rise and power will be turned off to the heating elements. If the start/stop input <NUM> is depressed mid-cycle, the cooking cycle will be discontinued, the elements will be turned off and the food rack <NUM> will rise.

Claim 1:
An electrical device for cooking and/or heating waffles or bread using a heating element (<NUM>), the device including:
a lower cooking plate (<NUM>) and an upper cooking plate (<NUM>), wherein each of the cooking plates includes a heating element;
a temperature sensor (<NUM>) configured to provide a temperature signal over time that is indicative of a measured temperature corresponding to a cooking temperature; and
a processor (<NUM>) configured to receive the temperature signal, the processor (<NUM>) configured to control power to the upper and/or lower cooking plates (<NUM>, <NUM>) for controlling the cooking temperature, which causes the cooking temperature to vary within a temperature range over time;
wherein
the processor (<NUM>) is configured such that the temperature range is subdivided into a plurality of temperature bands (<NUM>), wherein the measured temperature passes through the temperature bands (<NUM>) as the cooking temperature varies over time; and
the processor (<NUM>) is configured to assign a cooking time that is determined by the respective temperature band (<NUM>) about the time in which batter is added to the cooking plate (<NUM>, <NUM>).