Cooking hob, Household appliance and method of operating a cooking hob The invention is directed to a cooking hob, a household appliance and a method of operating a cooking hob.

Cooking hobs are known in many configurations. Tradition- ally, heating elements of cooking hobs are positioned in a fixed arrangement.

In order to cope with different shaped cooking utensils, in particular with different footprints of cooking utensils, it has been proposed to provide moveable heating elements. In US 6,017221, US 5,960,781 and KR 20100012627 cooking hobs are described which, to some extent, propose solutions adapted to varying cooking vessel dimensions.

However , there is still room for improvements, in partic- ular with respect to heating cooking vessels of different footprint s .

It is therefore an object of the invention to provide an alternative cooking hob, in particular adapted to cope with cooking vessels of different footprint geometrie s .

Further, under similar considerations, a cooking appliance and a method of operating a cooking hob shall be provided .

These objects in particular are solved by claims 1, 12 and 16. Further embodiments result from respective depen- dent claims . According to claim 1, a cooking hob is provided which comprises a cooking face with at least two heating ele- ments respectively adapted to heat cookware. The term "at least two" in particular shall comprise two, three or for heating elements. The term cooking face shall be understood to comprise areas, panes or plates of generally flat or planar confi ^¬ guration, on, below or to which heating elements, in particular gas hobs, i. e. gas cooking hobs, are mounted to. A cooking face may be or constitute a top part of a household oven.

In order to heat respective cookware, i. e. cooking uten ^¬ sils, such as pans, pots, roasting trays and the like, may be placed on top of at least one heating element to be heated up. Depending on the type of heating element heat or electromagnetic fields dissipating from a heating element impinge on the lower surface of the cookware which as a result heats up. A heating element in the sense of the present invention may be one of a inductive heating element comprising in ^¬ duction coils, radiation heating element, electrical re ^¬ sistance heating element and in particular a gas burner. Preferably, all of the heating elements are of the same type, albeit it is conceivable that heating elements of different types are provided. Heating elements such as inductive heating elements and radiation heating elements may be mounted below the cooking face. Heating elements such as electrical resistance heating elements and gas burners may be, at least partially, mounted above the cooking face .

The cooking hob further comprises at least one motion unit coupled to at least one a first heating element of the at least two heating elements. The motion unit is adapted and designed such that the first heating element is moveable along at least one tra ^¬ jectory of at least one of linear and curved type. The term "at least one trajectory" shall be understood to comprise a single trajectory or multiple different tra ^¬ jectories, in particular an array of different trajecto ^¬ ries. Note that different trajectories may at least in sections be identical. The term trajectory shall be un- derstood to be a path that can be followed by the first heating element within the boundaries defined by the mo ^¬ tion unit .

The term "of at least one of linear and curved type" in particular shall mean that a trajectory may comprise linear sections and/or curved sections of arbitrary curva ^¬ ture. Curved sections in particular shall comprise circu ^¬ lar, elliptical and parabolic shapes. The term "movable along" in particular shall mean that the center point, center of rotation, mass center and/or top surface center of the first heating element can fol ^¬ low the trajectory.

From a different but analog point of view or approach, the motion unit provides certain motional degrees of freedom, in particular translational and/or rotational degrees of freedom. Moving the first heating element within the boundaries given by the motional degrees of freedom leads to all possible trajectories, i. e. a re ^¬ spective array of trajectories. Note that a motion unit may be provided for selected heating elements, in partic ular also for each heating element provided within the cooking face .

With the proposed cooking hob, at least one second heat ^¬ ing element of the at least two heating elements and dif ferent from the first heating element, is positioned or can be positioned relative to the at least one trajectory such that in at least one trajectile position along the at least one trajectory, the first heating element and the at least one second heating element are so close to each other to establish a unique cooking zone.

The term "at least one trajectile position" in particular shall include single points on a trajectory and/or ranges or segments of a trajectory. The term "trajectile posi ^¬ tion" shall mean a position or point on the trajectory. The trajectile position may in particular be an end posi ^¬ tion of a trajectory or any intermediate point thereof. In a different trajectile position, the first heating element, and in particular also the at least one second heating element, are operable in single mode, i. e. no common cooking zone between the first and a second heat ^¬ ing element is established.

Providing at least one second heating element along, i. e. near or nearby the at least one trajectory shall mean, that either one or several respective second heating ele ^¬ ments may be provided that respectively can be used to establish unique cooking zones at respective trajectile positions. Note that any one or even all of the second heating elements may be implemented with a motion unit, i. e. may be implemented as a "first" heating element in the sense of claim 1.

In the case of having several, for example two or three, second heating elements establishing unique cooking zone with the first heating element in a single trajectile po ^¬ sition, a triple, quadruple etc. pair unique cooking zone can be established. Here it shall be mentioned, that triple, quadruple etc. unique cooking zones may also be implemented in cases where more than one first heating element , i . e . more than one movable heating element is provided .

The term "at least one motion unit" shall imply, that more than one motion unit may be provided, respectively coupled to a respective further first heating element, or even a second heating element. The above and below dis ^¬ cussion related to the first heating element shall apply mutatis mutandis to the further first heating element and second heating element. It shall be explicitly pointed out, that such a further first heating element may con ^¬ stitute a second heating element in the sense of the claims. This in particular means that not only the first heating element is moveable but also the second heating element is moveable along one or an array of second tra ^¬ jectories, in particular in such a way that unique heat ^¬ ing zones can be established.

In case that also the second heating element is moveable, it can be placed, i. e. moved to a respective trajectile position along the second trajectory or trajectories, and relative to the trajectile position of the first heating element such that the condition for establishing a unique cooking zone is fulfilled when the first heating element is in its trajectile position.

The motion unit may comprise guides, rails, turntables, platforms and other elements coupled to the first heating element and allowing movement thereof. The respective elements may be positioned on, within and/or below the cooking face. Below the cooking face in particular shall mean that the heating element, in particular together with the motion unit, may be positioned below a pane or top, for example made from glass or ceramic.

The term platform shall be understood broadly and in par ^¬ ticular shall mean any element or component system pro- vided to enable linear an or rotational movements. One particular embodiment of platform is a turntable to which the heating element s mounted t o . As can be seen, the proposed cooking hob is comparati ely flexible in establishing unique cooking zones adapted to different footprint sizes of cookware.

In an embodiment, the at least one trajectory is composed of at least one of a one-dimensional linear movement, two-dimensional movement, one-dimensional circular move ^¬ ment and two-dimensional circular movement.

A two-dimensional movement shall mean that the heating element is moveable within a two-dimensional area or plane parallel to the cooking face. It shall be noted that under certain instances the motion unit may be de ^¬ signed such that the first heating element is moveable in three-dimensions. This in particular would be the case if the first heating element is movable along at least one trajectory within a plane parallel to the cooking face and further is movable, at least in sections of the tra ^¬ jectory, in a direction perpendicular to the cooking face. Moving the first heating element perpendicular to the cooking face may for example be an option if the first heating element shall be adapted to be lowered or raised with respect to the cooking face.

A one-dimensional circular movement may be obtained if for example a first turntable, which is mounted rotatable about an inner axis, e. g. a center axis or an off-center axis, thereof within the cooking face, is provided, and the first heating element is mounted in a position dis ^¬ placed from the respective inner axis on or to the turnt- able. If a center axis of the turntable is used as a ro ^¬ tational axis, the first heating element is placed off- center to the rotation axis. When using turntables, it is preferred that in at least one rotational position of the turntable the first heat ^¬ ing element and one of the second heating elements mounted off the turntable of the first heating element are so close to each other to establish the unique cook ^¬ ing zone .

Note that several turntables may be provided respectively carrying a first heating element and which are adapted such that the first heating element establishes a unique cooking zone with a second heating element in a respec ^¬ tive rotational position. It shall be explicitly pointed out, that the number of turntables can be as much as heating elements are pro ^¬ vided within the cooking face.

It also shall be noted that unique cooking zones may ar- bitrarily be established with a second heating element which may be positioned fixedly, i. e. non-moveable , within the cooking face, or which may be positioned on a movable platform on within or below the cooking face. It shall be mentioned, that also at least one of the second heating elements may be mounted on a respective further turntable implemented in a similar manner than the turntable described above. A two-dimensional circular movement may be obtained if the heating element is rotatably placed or mounted to or on a primary, smaller turntable at a location off a respective rotation axis, and the smaller turntable in turn is rotatably placed on a secondary, larger turntable off its rotation axis. Rotational axes of the primary and secondary turntable in this case are offset from each other . In order to establish a linear, in particular one- dimensional or two-dimensional, movement, the motion unit may comprise a one-dimensional or two-dimensional linear guiding system, in particular rail system, along which the first heating element, preferably a platform to which the first heating element is mounted to, can be moved. In particular, if the rail system or platform is coupled with a respective turntable, trajectories with linear and/or circular sections can be obtained.

The first, and where applicable a second, turntable is preferably implemented as a circular, preferably flat, disk. The turntable may be mounted to a rotary mount which itself may be fixed to the cooking hob or a sup ^¬ porting element or frame thereof.

The motion unit, in particular linear guiding elements, in particular respective platforms, and/or turntables are preferably mounted, in particular arranged and posi ^¬ tioned, within the cooking face. The term within shall in particular relate to the lateral extension of the cooking face, which in general is aligned horizontally, i. e.

without inclination, during normal operation.

A turntable and/or platform, at least a section thereof, may project from the cooking face in a direction essentially perpendicular to the cooking face. However, it is preferred that the turntable and/or platform is essen- tially in plane with the cooking face, which shall mean that it is level with a respective section accommodating the turntable or platform. However, the turntable and/or platform may be positioned above the cooking face, which shall mean that at least outer sections of the turntable and/or platform overlap with the cooking face. In particular with turntables, the cooking face or a respective platform to which the turntable is mounted to may have a recess adapted in its geometry to the outer dimensions of the turntable. For example, the cooking face may comprise a circular recess accommodating therein at least a section of the turntable. Preferably a type of seal, having adequate heat resistance, is provided in a remaining gap between the recess and the turntable. A seal may also be provided in situations in which the turntable or moveable platform is mounted on and overlaps the cooking face.

A turntable or platform to which a turntable is mounted to may be connected to a guiding system arranged below the cooking face. In this case, slots, in particular guiding gates, may be provided in the cooking face, adapted to receive and guide mechanical connector ele ^¬ ments between guiding system and respective turntable and/or platform. The slots or guiding gates may be pro- vided with seals at least preventing dust, soil and/or overflowing foodstuff from penetrating through the cooking face .

With the proposed cooking hob, at least one first heating element, in particular gas burner, may be mounted off- center on or to the first turntable. Off-center shall mean that a vertical center axis of the heating element is offset from the vertical center axis of the turntable. This means, that upon rotating the turntable, the heating element, or in more general terms its center axis, ro ^¬ tates around the center axis of the turntable.

In an embodiment using primarily turntables, the cooking hob and its components advantageously are implemented such that at least in one rotational position of the first turntable the first heating element and one of at least one second heating elements mounted outside the first turntable s o close to each other so that a unique cooking i s established .

The term "establish" shall in particular be understood in the sense of make up, define and/or implement.

The term "unique cooking zone" shall in particular mean, that the individual cooking zones of the first and second heating elements merge together to make up a single, i. e. unique, cooking zone, having optimized, in particular almost uniform, heat output over their combined heating area. The unique cooking zone is enlarged, as compared to an individual cooking zone of a single heating element. Gas burners establishing a unique cooking zone may be po ^¬ sitioned such that a minimum distance between is zero. In case of circular heating elements, the minimum distance may range from 0 (zero) to 2.5 times the diameter of the larger heating element. In particular with gas burners, the gas burners establishing a unique cooking zone may face in correspondence of sparkplugs.

Note that properties and characteristics of the motion unit, in particular guiding system, turntable and/or platform mentioned and described above may, if applica ^¬ ble, apply mutatis mutandis to other motion units, in particular guiding systems, turntables and/or platforms mounted on or to the cooking face. The cooking hob as described above has the advantage, that the at least one first heating element can be moved relative to the cooking face in a comparatively simple way to obtain modified arrangements and cooking zones, in particular unique cooking zones. Further, using a guiding system, turntable and/or platform to obtain respective trajectories greatly simplifies constructional effort to implement a moveable heating element. The special configuration of the cooking hob makes it possible to merge two individual cooking zones of single heating elements to establish a unique cooking zone opti- mized for cooking utensils having comparatively large and/or special geometry footprints. Such cooking utensils may for example be elongated frying pans, roasting trays and the like, having oval footprints for example. Establishing the unique cooking zone is advantageous if cooking utensils have to be heated which have footprints larger, in particular considerably larger, than single cooking zones of the individual heating elements. Using the unique cooking zone, leads to optimized heating and heating efficiency.

It shall be noted, that in the configuration in which the first and respective second heating elements establish the unique cooking zone, the first and respective second heating element advantageously form a type of twin-type or twin-mode configuration. In a twin-type or twin-mode configuration, the heating excellence of a respective first and second heating element in particular exceeds the sum of heating excellence of respective single heat- ing elements.

It shall be mentioned that a further turntable and/or platform may be positioned or mounted next to the turnta ^¬ ble and/or platform of the first heating element. The term next to in particular shall mean that the first and second turntable and/or platform are arranged in imme ^¬ diate neighborhood of each other. In immediate neighbor ^¬ hood shall in particular mean that peripheral edges of the first and second turntable and/or platform at one point are as close, in particular as close as possible, to each other. Further, in establishing the unique cooking zone by using turntables, the first and second heating elements prefer ^¬ ably lie approximately on the connection line between the center axes of the respective turntables. This in partic ^¬ ular means that the distance between the first and second heating element, in particular the distance between respective center axes, is minimal or lies within a certain minimal range with respect to all possible positional configurations of the turntables.

Unique cooking zones established by using turntables may be obtained if a first heating element is mounted on a turntable and a second heating element is fixedly posi ^¬ tioned within the cooking face. However, the second heat ^¬ ing element may also be mounted moveably on a platform, in particular turntable.

In providing a two turntables and/or platforms movable in one or two dimensions, it is possible to flexibly adjust the alignment and/or orientation of the unique cooking zone. To a certain extent it is also possible to flexibly adjust the positional arrangement of individual cooking zones of respective first and second heating elements.

One further advantage of providing two turntables and/or platforms is that a heating element mounted on one of the turntables and/or platforms can be combined with several, distinct heating elements of the other turntable and/or platform. In particular, it is possible to obtain a more varied combination of different types of heating ele ^¬ ments, in particular if heating elements mounted to the first and second turntable and/or platform, respectively, have different characteristics, for example with respect to heating power. In addition, a greater variety of geometrical configurations, such as in-line configurations or square configurations, of the heating elements can be obtained . In an embodiment, the cooking hob comprises at least three heating elements, and the at least one motion unit is adapted such that in at least one second position of the first heating element along the trajectory all of the heating elements are aligned along a common line. For ex ^¬ ample, one first and two second heating elements may be provided . If turntables are used, at least two second heating ele ^¬ ments may be positioned circumferentially to the turnta ^¬ ble of the first heating element. The at least two second heating elements may be arranged and positioned such that at respective circumferential rotational positions of the turntable of the first heating element, the first and a respective second heating elements establish re ^¬ spective unique cooking zones.

Here, the at least one second heating element may be fixed on or to he cooking face. In this case, the second heating element can be considered as a stationary burner, whereas the first heating element can be considered a ro ^¬ tary heating element. In order to establish unique cooking zones, the second heating elements preferably are positioned sufficiently close to the turntable of the first heating element such that the conditions mentioned further above relating to the unique cooking zone can be fulfilled.

The distance between heating elements establishing a unique cooking zone may be selected from a range of dis ^¬ tances suitable for establishing the unique cooking zone. In particular in case of circular heating elements, the distance between cooking zones may range from 0 (zero) to 2.5 times the diameter of the larger heating element. The second heating elements may be distributed on or over the cooking zone such that, with particular respect to the inner axis, in particular center-axis, of the turnta ^¬ ble of the first heating element, a rotation angle of a turntable between a pair of subsequent second heating elements arranged in circumferential direction of the turntable is smaller than 180 degrees. Preferably, an an ^¬ gle between subsequent heating elements is 90 degrees. If three second heating elements are provided circumfe- rentially to the turntable and an angle between subse ^¬ quent heating elements is 90 degrees and one first heat ^¬ ing element is positioned on a respective turntable, in a certain rotational position a rectangular type of ar- rangement of the first and second heating elements can be obtained. In this rectangular arrangement the heating elements may be operable in non-twin mode, i. e. single mode, only. Different types of second heating elements may be used. The term "type" of heating elements in particular shall relate to at least one of size and heating power of a heating element. Using different types of heating ele ^¬ ments is not restricted to the aforementioned embodiment, but also applies to the embodiments mentioned further above and further below. Note that if several first heat ^¬ ing elements are provided, they can be of different type.

In particular in providing different types of heating elements and, as the case may be, allowing different dis ^¬ tances between first and second heating elements estab ^¬ lishing a unique cooking zone, different types of unique cooking zones can be obtained, which may differ from each other in particular in at least one of the overall size, geometry and overall heating power. Providing the possibility of establishing different types of unique cooking zones, a broader range of different sized cooking uten- sils can be covered.

In particular, if the heating elements are positioned or mounted on respective turntables but also in any other configurations, the motion unit preferably is adapted and the first and second heating elements preferably are po ^¬ sitioned such that in an in-line configuration, in particular an in-line rotational configuration of the turnt ^¬ able or turntables, all heating elements are positioned essentially along a common line.

With respect to the cooking face, which may be rectangu ^¬ lar, the common line preferably runs parallel to one of the side edges of the cooking face.

Beyond providing an advantageous arrangement of the heat ^¬ ing elements with respect to design issues, an in-line configuration may result in an advantageous, in particu ^¬ lar low, surface occupancy of the cooking face. In a low surface occupancy configuration of the heating elements, larger free surface areas, i. e. areas not occupied by heating elements, can be obtained. The free surface areas may provide additional free worktop or placement areas to a user of the cooking hob, to be used in particular for placing cooking utensils and other objects used or re ^¬ quired during cooking.

In a yet further embodiment, the motion unit is adapted such that the at least one first heating element is ro- tatable in clockwise and/or counterclockwise direction at least one of at least or exactly about 90°, 180°, 270° and 360°. This may for example be implemented such that respective turntables are rotatable in clockwise and/or counter-clockwise direction at least one of at least or exactly about 90°, 180°, 270° and 360°. Note that any in ^¬ termediate angles, such for example 70 degrees, may be used. Further, it is also possible that the turntables are adapted to be turned in endless rotation.

In one embodiment, the at least one motion unit comprises at least one latching mechanism adapted to latch the first heating element in at least one predefined position along a trajectory. The latching mechanism preferably is provided to latch the first and second heating elements in positions making up a unique cooking zone or in posi- tions making up single cooking zones.

Latching elements may be implemented as a stop restrict ^¬ ing translational and/or rotational movement. Latching elements and/or rotation stops may be used to latch the motion unit, in particular respective turntables and/or platforms, at respective positions along a trajectory, or to restrict movement thereof. Latching elements and/or rotational stops may in particular be provided in one or more circumferential positions of a turntable, in general at respective positions along a trajectory or path, in which positions unique cooking zone, i. e. twin-mode con ^¬ figurations, an in-line configuration or other configura ^¬ tions. A latching element or mechanism may also provide latched positions along the at least one trajectory such that all the heating elements can be best operated in single mode. Further, latching elements and/or rotation stops may in particular be used to restrict the rotation ^¬ al range of respective turntables to maximal allowed ro ^¬ tation angles, for example of about ± 90 degrees, ± 180 degrees, ± 270 degrees or about ± 360 degrees.

As already indicated further above, in certain preferred embodiments the at least one motion unit may comprise a platform, in particular movable platform to which the first heating element is mounted or coupled to. Note that if a turntable is used, it may be mounted to the plat ^¬ form. The platform may be mounted movably to the cooking face, in particular via a guiding unit or system posi- tioned at least one of on, within or below the cooking face . As has been already indicated, the moveable platform may comprise a turntable rotatable around an inner rotation axis thereof, wherein the first heating element is mounted to the turntable. Here a great variety of differ ^¬ ent trajectories may be obtained.

In a further preferred embodiment, the cooking hob com ^¬ prises a control system having control elements, i. e. at least one knob and/or a user interface, cooperating with an electronic controller unit, adapted to operate a re- spective one of the heating elements, and where applica ^¬ ble motors and/or actuators for moving, in particular translating and/or rotating the first and/or second heating element . The control system may in particular be adapted to con ^¬ trol single mode operation of each of the heating ele ^¬ ments. Here, a separate control element for each of the heating elements may be provided. With a special embodiment, however, the control system is adapted such that a pair of first and second heating ele ^¬ ments establishing a unique cooking zone is controllable by one common, i. e. in particular one single, control element .

Such a common or single control element may be designated a twin-mode control element. The twin-mode control ele ^¬ ment may be selected from one of the control elements of heating elements establishing the unique cooking zone. It is also possible, that a separate twin-mode control ele ^¬ ment for twin-mode operation, in particular for twin-mode operation of any twin-mode pair is provided. The control element may comprise a screen-like touch-sensitive and/or an acoustic-sensitive and/or remote controllable user in ^¬ terface, in particular for setting or resetting the twin- mode operational configuration.

In one further embodiment, the common control element is adapted to be activated in dependence of at least one of the trajectile position of the first and, where applica ^¬ ble, second heating element/s, in particular trajectile positions of the turntable and/or platform. As already stated, the common control element may be one of the sin ^¬ gle-mode control elements of respective heating elements, or the common control element may be an extra control element, in particular provided for twin-mode operation.

The more general idea behind this is that activation of a common control element goes along with establishing a unique cooking zone. Activation of the common control element may depend on the trajectile position, in partic- ular rotational angle, of respective heating element, in particular platform and/or turntable. If the rotational position corresponds to, or is close to a unique cooking zone, the common control element may be activated. At the same time, any other control element provided for single- mode operation of respective heating elements may be deactivated .

Inversely, if the rotational position leaves the twin- mode position or twin-mode range of positions, the common control element may be deactivated and respective single mode control elements may be activated again.

Proper activation and deactivation of control elements in particular shall ensure that control of the heating ele- ments is well defined at any instance. Activation and/or deactivation of single-mode and/or twin-mode control elements may be indicated or hig ^¬ hlighted by, for example, visual, in particular luminous, and further acoustic and/or haptic means.

A further embodiment addresses moving, in particular translating and/or turning, i. e. rotating, the first and/or second heating element, in particular respective turntables and/or platforms. The first and/or second heating element, in particular turntable and/or platform, may be moved, in particular turned, i. e. rotated, for example by an actuator, in particular motor, to respective trajectile, in particular, angular positions. Tra- jectile, in particular linear and/or angular positions of the first and, where applicable, second heating element may be selected automatically and/or according to indi ^¬ vidual user settings.

Angular positions may be, in particular automatically, selected from a predefined list of angular positions, such as ± 90 degrees, ± 180 degrees, ± 270 degrees or about ± 360 degrees or any other value in between. The predefined or selected angular settings may correspond to angular positions in which unique cooking zones, an in- line configuration and the like can be established.

In particular, is possible that the trajectile, particu ^¬ larly linear and/or angular position, of the first and/or second heating element, in particular platform and/or turntable, can be freely selected. Here, beyond estab ^¬ lishing unique cooking zones and so on, the geometrical arrangement of the heating elements, in particular rotat- able heating elements, can be adapted and optimized to respective sizes and geometries of cooking vessel placed or to be placed on the cooking hob. An electronic control unit may be provided to control a motor and/or an actuator used or provided for moving the first and/or second heating element. In one embodiment, at least one motion control may be provided, which is adapted and configured to move the first heating element, in particular in automated manner, along the at least one trajectory. A motion control can greatly simplify movement of heating elements, in partic- ular establishing unique cooking zones.

According to claim 11, a method of operating a cooking hob is provided. The cooking hob is essentially con ^¬ structed and designed according to any configuration and embodiment described further above and further below.

With the proposed method it is provided that in a twin- mode configuration of the first heating element and a second heating element, in which twin-mode configuration the first and second heating elements establish a unique cooking zone, the first and second heating elements are operable by a common control element, whilst in any non- twin mode configuration, the first and second heating elements are operable by a respective individual control elements .

In the case of using turntables for moving the first heating element, a twin-mode configuration of the first heating element and the second gas heating element mounted outside the first turntable, may be obtained in a specific twin-mode rotary position of the turntable.

Note that the proposed method and embodiments thereof may be applied to embodiments and configurations of cooking hobs, as described further above and further below. It shall be noted, that in the twin-mode configuration, the first and second heating elements establish a unique cooking zone. With respect to the twin-mode and to the unique cooking zone, the comments, description and defi- nitions given further above apply mutatis mutandis.

The control element may be a knob or similar. In more general, the control element may be a user interface, in particular of touch-display type, allowing in non-twin- mode configuration to independently control single heat ^¬ ing elements. Upon establishing the unique cooking zone, the twin-mode heating elements may be operated by a sepa ^¬ rate control element, including but not restricted to knobs, touch-sensitive elements, menus or task-menus of a touch-sensitive type control element and the like. Howev ^¬ er it is also possible that in twin-mode configuration, one of the individual control elements is used as a com ^¬ mon control element. The other one or other ones in this case may be deactivated.

Control elements adapted to control single heating ele ^¬ ments in non- twin-mode configuration may be activated upon leaving the twin-mode configuration. Upon entering a twin-mode configuration a respective one, or in case of a separate twin-mode control element, even both or all con ^¬ trol elements can be deactivated, whilst the twin-mode control element is activated. Activation and deactivation may be conducted automatically by an electronic control unit .

In an embodiment of the method, the common control ele ^¬ ment is activated and deactivated in dependence of at least one twin-mode trajectile position along the at least one trajectory. Here a twin-mode trajectile posi- tion shall mean a position on one of the at least one trajectory, in which the first heating element and the second heating element establish a common cooking zone. The twin mode trajectile position, i. e. the fact that the first heating element arrives at a twin-mode trajec ^¬ tile position, may be sensed or detected by sensor ele- ments, in particular adapted to sense linear and/or rota ^¬ tional movements. The actual position of the first heat ^¬ ing element, and where applicable the second heating ele ^¬ ment, may be sensed or detected continuously or selec ^¬ tively, e. g. at predefined time intervals.

In a further embodiment, the first heating element may be automatically moved along a trajectory according to a setting of a user or program for automatically or semi- automatically operating the cooking hob.

The user setting may be inputted via a user interface. For example the user setting may comprise a type of com ^¬ mand such as "set twin-mode configuration" or "set non- twin-mode configuration", or similar. After inputting the user setting, and preferably after confirmation, the first heating element, and where applicable the second heating element, may be automatically moved along the at least trajectory, such that the twin-mode or non-twin- mode configuration is established.

In the embodiment allowing automatic movement, a safety mechanism or routine may be provided. The safety mechan ^¬ ism may for example block automatic movement in instances where objects, in particular cookware, are placed on the cooking hob, cooking face and/or heating elements. Movement of the heating element may cause objects placed on the cooking hob and the like to overturn or be pushed from the cooking hob and the like, which may result in dangerous situations or even physical injuries to users or persons near the cooking hob. The safety mechanism and/or routine may comprise sensors for sensing objects placed on the cooking hob, cooking face and/or heating elements .

In a yet further embodiment of the method, the twin-mode configuration may be indicated by visual, acoustic and/or haptic means, i. e. special signs, on a user interface. The non- twin-mode configuration may be indicated by simi ^¬ lar means . In addition, it shall be mentioned, that the status of the control element or control elements can be indicated by visual means. The term status in this connection in particular shall cover activation or deactivation for twin-mode and/or non- twin-mode , i. e. single mode, opera- t i on .

According to claim 15, a household appliance is provided, which comprises at least one cooking hob according to any of the above described configurations and embodiments.

In an embodiment of the household appl lance, an electron- ic control unit may be provided which is adapted and con- figured to operate the household appli ance according to the proposed method or any embodiments thereof .

For advantages and advantageous effects applying to the household appliance reference is made to the description above . In all, it can be seen that the proposed cooking hob, household appliance and method are well suitable for han ^¬ dling cooking vessels of different footprint geometries. Adaptation to different footprint geometries allows ener ^¬ gy optimized heating. One further advantage is that re- spective cooking vessels can be heated according to re ^¬ spective needs. In particular cooking vessels can be heated more uniformly, thereby avoiding local overheating and/or burnt food.

Exemplary and selected embodiments will now be described in connection with the annexed figures, in which:

Fig. 1 shows a schematic top view of a cooking hob of a first configuration; Fig. 2 shows a schematic top view of a cooking hob of a second configuration;

Fig. 3 shows a schematic top view of a cooking hob of a third configuration;

Fig. 4 shows a schematic top view of a cooking hob of a fourth configuration;

Fig. 5 shows a schematic top view of a cooking hob of a fifth configuration; and

Fig. 6 shows a schematic perspective view of a house ^¬ hold appliance. In the figures, like elements are designated by like ref ^¬ erence signs .

Fig. 1 shows a schematic top view of a cooking hob 1 of a first configuration. The cooking hob comprises a cooking face 2. On or to the cooking face 2 there is mounted a first turntable 3, which is part of a moving unit of the cooking hob 1. The first turntable 3 is mounted rotatably around its center axis 4 and within the cooking face 2. In other words, the first turntable 3 is integrated into the cooking face 2 in a rotatable manner such that it can pivot around the center axis 4 running in vertical direc ^¬ tion during normal operation of the cooking hob 1. One first heating element 5 is mounted on the first turn ^¬ table 3 in an off-center position. The first heating element 5 is of circular design, which is a general, but not mandatory characteristic of heating elements used for household cooking hobs. The heating elements may for ex ^¬ ample have elongated, in particular oval, shapes instead.

The off-center position in the present case is such that the outer the edge of the first heating element 5 is close to the outer rim of the first turntable 3.

With the shown embodiment, the radius of the first turnt ^¬ able 3 is larger than the diameter of the first heating element 5. In other embodiments, this situation may be different. In particular it is possible that the diameter of the first heating element 5 equals or even is larger than the radius of the first turntable 3. Within the cooking face 2 and outside the first turntable 3 there are provided second heating elements 6. The second heating elements 6 in the present case also are of circular design. Further, the second heating elements 6 have different sizes, which in the present case shall in- dicate that they have different heating powers.

The second heating elements 6 are distributed circumfe- rentially to the first turntable 3 and positioned close to the outer rim of the first turntable 3. The second heating elements 6 are spaced from each other by 180 and 90 degrees, respectively.

In the configuration shown in Fig. 1, in which the first heating element 5 is represented by solid lines, the first heating element 5 is so close to the left-hand side second heating element 6, such that they establish a unique cooking zone 7. A unique cooking zone 7 in particular shall be defined by the fact that in and over a unique cooking zone 7 a com ^¬ paratively unique heat distribution and emission is ob- tained. The unique cooking zone itself in general is larger than the sum of respective individual cooking zones. This in turn means that a cooking vessel of elon ^¬ gated shape can be heated more efficiently, in particular more uniformly, in particular as far as the footprint area of the cooking vessel is concerned.

The first turntable 3 as shown in Fig. 1 may be rotated clockwise and counterclockwise by at least 270 degrees, which is indicated by a respective double arrow. Rotating the first heating element 5 to other positions,

represented in Fig. 1 by grey-shaded first heating ele ^¬ ment 5' positioned in a top, bottom and right-hand posi ^¬ tion, leads to different heating element layouts and, as the case may be, different unique cooking zones.

In the top-position, the first heating element 5'

represents a single heating element to be operated in single mode only. In the bottom and right-hand position, the first heating element 5' again is close to respective second heating element 6 such that respective further unique cooking zones can be established. For the sake of clarity, the further unique cooking zones are not indi ^¬ cated in Fig. 1. The further unique cooking zones differ from the unique cooking zone 7 in their size and heating power, as the first heating element 5 is combined with different types of second heating element 6 differing from each other for example in size and heating power.

The configurations in which the first heating element 5, 5' establishes a unique cooking zone with respective second heating element 6 can be designated as twin-mode configurations. The configuration in which the first heating element 5 is not quite close to a second heating element 6, i. e. the top position in Fig. 1, can be des- ignated as a non-twin mode or single mode configuration.

Fig. 2 shows a schematic top view of a cooking hob 1 of second configuration.

The second configuration differs from the first configu ^¬ ration shown in Fig. 1 in that the first turntable 3 car ries two first heating elements 5 and that only two second heating elements 6 are provided. The second heat ^¬ ing elements are positioned on left-hand and right-hand sides of the first turntable 3, respectively.

The two first heating elements 5 are positioned off- center on the first turntable 3 and as close as possible to the outer rim of the first turntable 3. Further, the first heating elements 5, more specifically their center axes, lie on a line passing through the center axis 4 of the first turntable.

In the configuration depicted by solid-lines, the two first heating elements 5 are so close to the left-hand and right-hand second heating elements 6, respectively, so that respective two unique cooking zones can be estab lished. Respective pairs of first 5 and second heating elements 6 may be operated in twin-mode. For the sake of clarity, only one unique cooking zone 7 is explicitly shown in Fig . 2.

In the configuration depicted in a grey-shade, in which the first heating elements 5' are rotated by 90 degrees as compared to the solid-line configuration, all of the heating elements, i. e. the two first heating elements 5 and the two second heating elements 6, are operable in single mode, i. e. non-twin mode. In the solid-line configuration in Fig. 2, in which two unique cooking zones 7 can be simultaneously established, all of the first heating elements 5 and second heating elements 6, in more detail their center axes, are posi- tioned on a common line. This configuration represents an in-line configuration which may be advantageous for cooking hob design aspects. In addition, an in-line configu ^¬ ration may lead to an advantageous arrangement of the heating elements, in which a comparatively large free area or space is obtained which can be used as additional workspace for placing different kinds of objects, e. g. cooking utensils and the like.

Fig. 3 shows a schematic top view of a cooking hob of a third configuration. Similarly to the second configura ^¬ tion, a first turntable 3 with two first heating elements 5 is provided.

Further, and in contrast to the first and second configu- ration, a second turntable 8 is provided on which two second heating elements 6 are mounted. The two first heating elements 5 and the two second heating elements 6 are positioned on lines running through respective center axes 4 of the first 3 and second turntable 8. As can be seen, respective first heating elements 5 and respective second heating elements 6 are positioned offset by 180 degrees on the first 3 and second turntable 8, respec ^¬ tively. Note, that more that two turntables may be pro ^¬ vided, in particular, a turntable may be provided for each of the heating elements 5.

In the configuration shown in Fig. 3, the first 3 and second turntable 8 can be rotated by 360 degrees about respective center axes 4. Unique cooking zones, such as the unique cooking zone 7 indicated in Fig. 3, can be ob ^¬ tained if the first 5 and second heating elements 6 are in in-line configuration. Considering the third embodi- ment, the unique cooking zone 7 in all instances lies be ^¬ tween the center axes 4 of the first 3 and second turnta ^¬ ble 8. Different unique cooking zones may be established, which may differ from each other in size, shape and/or heating power depending on the mating of respective first

5 and second heating elements 6.

The configuration shown in Fig. 3 allows the establishment of four different unique cooking zones according to all possible combinatory combinations of the first 5 and second heating elements 6. Note that the number of combi ^¬ natory combinations is dependent on at least on the size and heating power of first 5 and second heating elements

6 mounted to the first 3 and second turntable 8. Note that it is not mandatory that unique cooking zones are established in all possible combinatory combinations.

By turning the first 3 and second turntable 8 such that no pair of first 5 and second heating elements 6 estab- lish a unique cooking zone 7, respective non-twin mode configurations can be obtained. In principle, it is poss ^¬ ible to allow any rotational positions of the first 3 and second turntables 8 for establishing non-twin mode configurations. In this case, a great variety of possible ar- rangements of the first 5 and second heating elements 6 is possible. This in turn allows for flexible adaptation of the arrangement of the first 5 and second heating ele ^¬ ments 6 to respective cooking vessel sizes placed or to be placed on the cooking hob 1.

It shall be mentioned, that the cooking hob may be adapted such that non-twin mode configurations can be ob ^¬ tained only at predefined rotational positions of the first 3 and/or second turntable 8. As an example, in the configuration shown in Fig. 3 only one single non-twin mode configuration may be provided, in which the first 3 and second turntable 8 are rotated by 90 degrees with re- spect to their in-line configuration .

One feature pertaining to any of the configurations shown and described in connection with Fig. 1 to 3 is that a control system may be provided which is adapted to con ^¬ trol twin-mode and non-twin mode operation of first 5 and second heating elements 6. The control system may be adapted such that first 5 and second heating elements 6 establishing a unique cooking zone 7 are controllable by a single, common control element. Such a configuration greatly enhances ease of operation of the cooking hob 1.

Controlling first 5 and second heating elements 6 by a common control element may be accompanied with activation and/or deactivation of control elements. In more detail, single-mode control elements, e. g. control knobs, of re ^¬ spective heating elements establishing a unique cooking zone may be deactivated whilst a control element for twin-mode operation is activated, and vice versa. Note that a control element for twin-mode operation may be one of the control elements provided for non-twin mode, i. e. single-mode, operation. In the alternative, a separate control element for twin-mode operation may be provided.

The first turntable 3 and, where applicable, second turn ^¬ table 8 may be rotated manually. However, in particular in terms of ease of use, rotation of the first turntable 3 and, where applicable, second turntable 8 may be con- ducted automatically. Here a controller and respective motors and/or actuators may be provided.

Fig. 4 shows a schematic top view of a cooking hob 1 of a fourth configuration. The cooking hob 1 differs from that of Fig. 1 to 3 in that also linear translational move ^¬ ments of the first heating element 5 are possible. In the situation shown in Fig. 4, the first heating element 5 is rotated in a position in which a unique cooking zone 7 is established with the bottom right second heat ^¬ ing element 6. Rotating the first heating element 5 by 180° into position 5' will lead to a configuration in which the heating elements are positioned in the corners of a rectangle and operable in single mode.

The turntable 3 of the embodiment shown in Fig. 4 is coupled to rail system of linear type, schematically in ^¬ dicated by two arrows. The rail system is adapted and de ^¬ signed such that a linear movement of the turntable 3 as such is possible. Presently, the rail system provides movement in two, mutually perpendicular, linear direc- t ions .

It can be readily recognized, that the first heating ele ^¬ ment 5 can be moved along a trajectory of linear and/or circular shape. For example, in order to establish a twin-burner configuration between the first heating element 5 and the second heating element 6 positioned top left, the turntable may be rotated by -90° (or 270°) and then be moved to the left about a distance indicated by a respective arrow. Note that the linear and/or rotational movements can be conducted in arbitrary sequence, in par ^¬ ticular concurrently. Hence, the first heating element 5 may be moved along trajectories of an array of trajecto ^¬ ries. For establishing a twin-mode between the first heating element 5 and the second heating element 6 arranged bot ^¬ tom left, the turntable can be moved downwards along the linear rail or guiding system and be rotated such that the first heating element 5 is in twin-mode configuration with the bottom left second heating element 6. One possible trajectory 12 along which the first heating element 5 may be moved is indicated in Fig. 4 by a dashed line. Note, that the trajectory 12 shown in Fig. 4 may have a different course or geometry, in particular de- pending on the starting position. Further it shall be noted, that the succession of rotational movements and translational movements may be different. In particular it is possible that rotational movements and translation ^¬ al movements are conducted not only successively but also concurrently.

Fig. 5 shows a further schematic top view of a cooking hob 1 in a fifth configuration. In this configuration there are provided two first heating elements 5, present- ly the top right and bottom left heating elements. In contrast to the previous embodiments, the first heating elements 5 are not arranged on a turntable. In the present case, the first heating elements are moveable along liner trajectories only. Exemplarily, double arrows show how the first heating elements 5 may be moved via motion units to which the first heating elements are re ^¬ spectively coupled. The motion unit may comprise a rail system and the like for example. The configuration in Fig. 5 allows movements which are essentially parallel to the short and long sides of the cooking face 2. It shall be noted, that other linear movements may be used, such as for example linear move ^¬ ments running diagonally to the cooking face 2. In Fig. 5, one possibility of diagonal movement is exemplarily shown by a dashed double arrow, indicating that the top right first heating element 5 may be moved in diagonal direction of the cooking face 2. It shall further be noted, that it lies within the scope of the invention if all the heating elements of the cook- ing face 2 are moveable in at least one a linear and curved, in particular circular, movement

Fig. 6 shows a household appliance 9 comprising a cooking hob 1 in a configuration according to the first configu ^¬ ration shown and described in connection with Fig. 1.

Note that the cooking hob 1 may be of any other configu ^¬ ration described further above. The appliance 9 comprises a first control knob 10 adapted in particular for controlling the first heating element 5 mounted to the turntable 3. Further, the appliance com ^¬ prises second control knobs 11 adapted for controlling respective second heating elements 6. In a twin-mode con- figuration, as for example shown in Fig. 4, the control knob 11 of the second heating element 6 establishing the unique cooking zone together with the first heating element 5 is deactivated whilst the first control knob 10 is switched to twin-mode operation in which the first 5 and second heating element 6 establishing the unique cooking zone can be operated together. If all heating elements are in non-twin mode operation, all control knobs are in non-twin mode operational mode, in which each of the heating elements can be operated in single mode.

The method of operating the cooking hob 1 easily can be derived from the description above. In particular, it may be provided that in a twin-mode configuration in which the first 5 and second heating elements 6 establish a unique cooking zone 7, the first 5 and second heating elements 6 are operable by a common control element 10, whilst in an any non twin-mode configuration, the first 5 and second heating elements 6 are operable by respective individual control elements. Further reference is made to the description above and further above. List of reference numerals

1 cooking hob

2 cooking face

3 first turntable

4 center axis

5 first heating element

5 ' first heating element

6 second heating element

7 unique cooking zone

8 second turntable

9 household appliance

10 first control knob

11 second control knob