GB2516174A

GB2516174A - Determining a characteristic of a cooking appliance with a key

Info

Publication number: GB2516174A
Application number: GB1413615.4A
Authority: GB
Inventors: Matthew Roberts; James Meddick; Michael James; Glyn Hauser
Original assignee: Morphy Richards Ltd; Morphy Richards NI Ltd
Current assignee: Morphy Richards Ltd; Morphy Richards NI Ltd
Priority date: 2012-10-12
Filing date: 2012-10-12
Publication date: 2015-01-14
Anticipated expiration: 2032-10-12
Also published as: GB201413615D0; GB2506905A; GB201218314D0; GB2506905B; HK1200639A1; GB2516174B

Abstract

A cooking appliance (fig 1) for a cooking hob has a vessel containing a chamber and a key having plural switch engaging regions (fig 13, 306) providing a code that identifies at least one characteristic of the appliance. A cooking hob (fig 5) comprises a controller 602 connected to a driver 604 of an inductive coil 510 and a key decoder 1012 comprising plural switches (fig 10, 1016). When the key is placed in socket 1102 of the decoder it provides a code to the controller indicating a characteristic of a cooking appliance associated with the key. The power output of the induction coil can be controlled depending on the characteristic which can relate to a type of appliance or a cooking profile including cooking temperature and time. The key can be releasable mounted in a lid or handle of the appliance and include a key-shaped position interlock. The switch key can be replaced with a magnetic key having plural magnets (fig 4, 206) to operate plural magnetic field sensors in the decoder to provide the code indicating the appliance characteristic.

Description

DETERMINING A CHARACTERISTIC OF A

COOKING APPLIANCE WITH A KEY

Field of the Invention

[0001] The present invention relates to cooking appliances, cooking hobs and a method for determining a characteristic such as a cooking profile for a cooking appliance that has an associated key. The invention is particularly useful for identifying a cooking profile or cooking characteristic to eliminate or at least reduce the requirements for a user to select cooking temperatures (or hob settings) for a specific cooking appliance.

Background of the Invention

[0002] There are numerous cooking appliances that can be used on cooking hobs such as induction hobs. These appliances offer a wide range of cooking modes such as boiling, griddling, poaching, steaming, simmering, blanching, Sous Vide style cooking and frying. After placing a cooking appliance on a cooking hob the user then typically selects a cooking mode by interacting with control settings of the hob. This interaction may be inconvenient especially when the user has wet hands, or food residue on their hands, resulting from preparing food that is to be cooked on the hob. It would therefore be useful if the cooking hob identifies a cooking characteristic or cooking profile of the cooking appliance that can be used to set control cooking settings of the cooking hob.

[0003] Some cooking appliances are known to have radio transmitters for wireless communication with cooking hobs. This wireless communication can be used to provide characteristics of the cooking appliance to the cooking hob.

However, the radio transmitter should either be in a watertight chamber or removable from the appliance so that moisture does not come into contact with the circuitry of the transmitter during washing of the appliance. Furthermore, these appliances are relatively expensive due to the additional circuitry of the transmitter and also require a battery or other power storage means. Such transmitters also need to be kept away from the high temperatures and thus are typically stored in a handle of the appliance which can be at a distance of as much as 10 to 15 cm from the cooking hob. It would therefore be beneficial if the characteristics of the appliance could be communicated to the induction hob without the need for radio transmitters.

Summary of the Invention

[0004] According to a first aspect of the present invention, there is provided a cooking appliance for use on a cooking hob, the appliance comprising: a cooking vessel containing a chamber therein; and a magnetic key associated with the appliance, the magnetic key having plurality of magnets providing a code that identifies at least one characteristic of the cooking appliance. :is

[0005] Preferably, the magnetic key is releaseably mountable to the cooking appliance.

[0006] Suitably, the magnetic key is releaseably mountable to a handle of the cooking appliance.

[0007] Preferably, the cooking appliance has a cover for covering the chamber and wherein a handle of the cover has a recess for complementary engagement with the magnetic key [0008] Suitably, the magnetic key has a user interface positioning interlock.

[0009] The cooking appliance may preferably include an appliance positioning interlock for operatively coupling with an appliance positioning interlock engagement member of a cooking hob to thereby position the cooking appliance on the cooking hob in a predefined location.

[0010] There may be a ferrous based inductive heating member associated with the vessel.

[0011] Suitably, the vessel includes a base for seating the cooking appliance on a cooking hob.

[0012] Preferably, there is a ferrous based inductive heating member forming at least part of the base [0013] According to a second aspect of the present invention, there is provided a set of cooking appliances, each of the appliances comprising the appliance according to the first aspect of the present invention, wherein the code of each magnetic key uniquely identifies its associated appliance from the other appliances in the set.

[0014] According to a third aspect of the present invention, there is provided cooking hob comprising: at least one inductive coil; a driver having an output coupled to the inductive coil; a controller coupled to the driver; and a magnet key decoder coupled to the controller, the magnetic key decoder

comprising a plurality of magnetic field sensors,

wherein, in operation, when a magnetic key is placed proximal to the magnetic key decoder, the magnetic key decoder provides a code to the controller, the code being indicative of a characteristic of a cooking appliance associated with the magnetic key.

[0015] Suitably, the characteristic of a cooking appliance relates to the type of cooking appliance.

[0016] Preferably, the characteristic of the cooking appliance relates to a cooking profile of the appliance.

[0017] Suitably, the magnetic field sensors are Hall Effect sensors.

[0018] Preferably, the magnet decoder provides the code which is dependent upon magnetic field polarities detected from magnets the magnetic key.

[0019] The cooking hob may suitably include an appliance positioning interlock engagement member.

[0020] Suitably, wherein there is at least one appliance engagement sensor associated with the appliance positioning interlock engagement member.

[0021] Preferably, the magnetic key decoder has a key positioning interlock for engagement with a user interface positioning interlock of the magnetic key.

[0022] According to a fourth aspect of the present invention, there is provided a method of determining a characteristic of a cooking appliance seated on a cooking hob, the method being performed by circuitry associated with the cooking hob, and the method including: decoding a magnetic code to identify a characteristic of a cooking appliance associated with a magnetic key, wherein the magnetic code is provided by magnetic fields supplied from a plurality of magnets on the magnetic key; and controlling a power output of a driver coupled to an inductive coil of the hob, the controlling being dependent on the characteristic.

[0023] Suitably, the method includes a prior step of detecting the cooking appliance seated on the cooking hob.

[0024] Preferably, the cooking appliance is the appliance according to the first aspect of the present invention.

[0025] Suitably, the cooking hob is the cooking hob according to the third aspect of the present invention.

[0026] Preferably, the characteristic of a cooking appliance is a cooking profile identifier.

[0027] Suitably, the cooking profile identifier indicates a power output requirement of the driver.

[0028] According to fifth aspect of the present invention there is provided a magnet key decoder, the magnetic key decoder comprising a plurality of

magnetic field sensors,

and wherein, in operation, when a magnetic key is placed proximal to the magnetic key decoder, the magnetic key decoder provides a code indicative of a characteristic of a cooking appliance associated with the magnetic key.

[0029] According a sixth aspect of the present invention there is provided a cooking appliance for use on a cooking hob, the appliance comprising: a cooking vessel containing a chamber therein; and a key associated with the appliance, the key having plurality of switch engaging regions providing a code that identifies at least one characteristic of the cooking appliance.

[0030] Suitably, the key is releaseably mountable to the cooking appliance.

[0031] Preferably, the key is releaseably mountable to a handle of the cooking appliance.

[0032] Suitably, the cooking appliance has a cover for covering the chamber and wherein a handle of the cover has a recess for complementary engagement with the key.

[0033] Preferably, the key has a user interface positioning interlock.

[0034] Suitably, there is an appliance positioning interlock for operatively coupling with an appliance positioning interlock engagement member of a cooking hob to thereby position the cooking appliance on the cooking hob in a predefined location.

[0035] There may be a ferrous based inductive heating member associated with the vessel.

[0036] Suitably, the vessel includes a base for seating the cooking appliance on a cooking hob.

[0037] Preferably, there is a ferrous based inductive heating member forming at least part of a base of the vessel.

[0038] According to a seventh aspect of the present invention there is provided a set of cooking appliances, each of the appliances comprising the appliance according to the sixth aspect of the present invention, wherein the code of each key uniquely identifies its associated appliance from the other appliances in the set.

[0039] According to an eighth aspect of the present invention there is provided a cooking hob comprising: at least one inductive coil; a driver having an output coupled to the inductive coil; a controller coupled to the driver; and a key decoder coupled to the controller, the key decoder comprising a plurality of switches, wherein, in operation, when a key engages with the key decoder, the key decoder provides a code to the controller, the code being indicative of a characteristic of a cooking appliance associated with the key.

[0040] Preferably, the characteristic of a cooking appliance relates to the type of cooking appliance.

[0041] Suitably, the characteristic of the cooking appliance relates to a cooking profile of the appliance.

[0042] Preferably, the hob includes an appliance positioning interlock engagement member.

[0043] Suitably, there is at least one appliance engagement sensor associated with the appliance positioning interlock engagement member.

[0044] Preferably, the key decoder has a key positioning interlock for engagement with a user interface positioning interlock of the key.

[0045] According to a ninth aspect of the present invention there is provided a method of determining a characteristic of a cooking appliance seated on a cooking hob, the method being performed by circuitry associated with the cooking hob, and the method including: decoding a code to identify a characteristic of a cooking appliance associated with a key, wherein the code is provided by switch engaging region on the key; and controlling a power output of a driver coupled to an inductive coil of the hob, the controlling being dependent on the characteristic.

[0046] Suitably, the method includes a prior step of detecting the cooking appliance seated on the cooking hob.

[0047] Preferably, the cooking appliance is the appliance according to the sixth aspect of the present invention.

[0048] Suitably, the cooking hob is the cooking hob according to the eighth aspect of the present invention.

[0049] Preferably, the cooking profile identifier indicates a power output requirement of the driver.

[0050] According to a tenth aspect of the present invention there is provided a key decoder, the key decoder comprising a plurality switches, wherein in operation, when a key engages with the key decoder, the key decoder provides a code indicative of a characteristic of a cooking appliance associated with the key.

[0051] Other aspects of the present invention are set out in the claims.

Brief Description of the Drawings

[0052] For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which: Figure 1 is a side view of a cooking appliance in accordance with a preferred embodiment of the present invention; Figure 2 is a top plan view of the cooking appliance of Figure 1 in accordance with a preferred embodiment of the present invention; Figure 3 is a side view of a magnetic key in accordance with a preferred embodiment of the present invention; Figure 4 is an underside plan view of the magnetic key in accordance with a preferred embodiment of the present invention; Figure 5 is a top plan view of a cooking hob in accordance with a preferred embodiment of the present invention; Figure 6 is a schematic block diagram of a cooking hob circuit in accordance with a preferred embodiment of the present invention; Figure 7 illustrates a user interface of the cooking hob of Figure 5 in accordance with a preferred embodiment of the present invention; Figure 8 is schematic circuit diagram of a sensor circuit that forms part of a magnetic key decoder in accordance with a preferred embodiment of the present invention; Figure 9 is a top plan view of a cooking appliance in accordance with a further preferred embodiment of the present invention; Figure 10 is a schematic block diagram of a cooking hob circuit in accordance with another preferred embodiment of the present invention; Figure 11 illustrates a user interface of the cooking hob of Figure 5 in accordance with another preferred embodiment of the present invention; Figure 12 illustrates a user interface of the cooking hob of Figure 5 in accordance with a further preferred embodiment of the present invention; Figure 13 illustrates an underside plan view of a key in accordance with a further preferred embodiment of the present invention; Figure 14 illustrates an underside plan view of a key in accordance with another further preferred embodiment of the present invention; and Figure 15 is flow diagram illustrating a method of determining a characteristic of a cooking appliance seated on the cooking hob of Figure 5 in accordance with a preferred embodiment of the present invention.

Detailed Description of the Embodiments

[0053] There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances] well known methods and structures have not been described in detail so as not to

unnecessarily obscure the description.

[0054] Referring to Figure 1 there is illustrated a side view of a cooking appliance 100 in accordance with a preferred embodiment of the present invention. The cooking appliance 100 is for use on a cooking hob, such as an induction hob, and the appliance 100 includes a cooking vessel 102 containing a chamber 104. There is an appliance positioning interlock 110 in the form of a recess in a base 112 of the cooking appliance 100. The cooking appliance 100 also has handles 114 and there is a lid or cover 116 placed on top of the vessel 102 for closing/sealing the chamber 104 during cooking.

[0055] The cover 116 has a handle 118 and there is a magnetic key 120 associated with the appliance 100 that is releasably mountable to the handle 118.

More specifically, the handle 118 has a recess 122 for complementary engagement with the magnetic key 120. Hence when the magnetic key 120 is engaged in the recess 122, the magnetic key appears to be part of the handle 118.

[0056] There is a ferrous based inductive heating member 130 associated with the vessel 102 and typically forms part of the base 112. In this embodiment the ferrous based inductive heating member 130 is disc shaped and is forged/formed or integrally moulded to the vessel 102 which is made typically from aluminum or other non-ferrous based metals or metal alloys. . The inductive heating member 130, in operation, heats up when placed proximal to an alternating electromagnetic filed or a pulsed electromagnetic filed as is well known in the art. Also, the base 112 provides for seating the cooking appliance 100 on a cooking hob in a seating plane PS.

[0057] Referring to Figure 2 there is illustrated a top plan view of the cooking appliance 100 in accordance with a preferred embodiment of the present invention. As illustrated, the magnetic key 120 is mounted to the handle 118 by insertion of the magnetic key 120 into the recess 122. This allows the key 120 to be easily removed from the handle 118 and the magnetic key 120 in this embodiment is a disc and looks as though it is part of the handle 118.

[0058] The magnetic key 120 has plurality of magnets 206 providing a magnetic field code MC that identifies at least one characteristic of the cooking appliance 100. This characteristic can typically be: the type of appliance; the type of cooking provided by the appliance; the required cooking profile of the appliance; a default cooking time for the appliance; or the required inductive power to be supplied to the appliance. The magnets 206 are mounted in the magnetic key 120 and they are spaced apart so that the interference (interaction of the magnetic fields of the magnets 206) is negligible for the purpose of the provision of the magnetic field code MC. Also a housing 210 of the magnetic key is formed from a non-ferrous material such as glass or plastics so as not to affect or unduly alter the paths of the magnetic flux or fields from the magnets 206.

[0059] Referring to Figure 3 there is illustrated a side view of the magnetic key 120 in accordance with a preferred embodiment of the present invention.

The magnetic key 120 as illustrated has been removed from the handle 118 and at an underside surface 302 there is a user interface positioning interlock 304.

This interlock 304, as illustrated, protrudes from the underside surface 302.

[0060] Referring to Figure 4 there is illustrated an underside plan view of the magnetic key 120 in accordance with a preferred embodiment of the present invention. In this embodiment, the user interface positioning interlock 304 that is a recess having an outline resembling a key. Also, the positions of the magnets 120 can be seen relative to the user interface positioning interlock 304.

[0061] Referring to Figure 5 there is illustrated a top plan view of a cooking hob 500 in accordance with a preferred embodiment of the present invention.

The cooking hob 500 (an induction hob) in this embodiment includes a cooking appliance support surface 502 and two cooking rings 504 each of which has an appliance positioning interlock engagement member 506 which in this embodiment is a protrusion on the support surface 502. The two cooking rings 504 have perimeter markings 508 displayed on the support surface 502 that are essentially for aesthetic appeal and for use as a marker for guiding a user of where to place the cooking appliance 100. Each of the cooking rings 504 have an inductive coil or coils 510 (shown in phantom) under the cooking appliance support surface 502 and the coils 510 are positioned within the perimeter markings 508.

[0062] Associated with each appliance positioning interlock engagement member 506 are two appliance engagement sensors 520 and 522 that in this embodiment are toggle switches with their actuators protruding from an upper surface (for sensor 520) and side surface (for sensor 522) of the interlock engagement member 506. However, it is envisaged that other forms of appliance engagement sensors can be used such as photo sensors, magnetic field sensors, capacitance sensors and inductance sensors. It is also envisaged that only one of the appliance engagement sensors 520 and 522 is required in some embodiments and in further embodiment the need for such sensors could possibly be removed. However, the use of both engagement sensors 520 and 522 offers additional safety and reliability.

[0063] The cooking hob 500 also has a user interface 524 that allows a user to view information such as cooking temperatures, settings, cooking times as well as allowing the user to switch the cooking hob 500 on and off, adjust cooking settings, adjust temperatures and adjust cooking timing. The user interface 524 is also adapted to communicate with the magnetic key 120 as will be described below.

[0064] Referring to Figure 6 there is illustrated a schematic block diagram of a cooking hob circuit 600 in accordance with a preferred embodiment of the present invention. The cooking hob circuit 600 is part of the cooking hob 500 and the cooking hob circuit 600 includes the inductive coil or coils 510 coupled to an output of a driver 604. A controller 602 is coupled to the driver 604 and there is also an appliance detector 606 having an output (or outputs) coupled to the controller 602. The appliance detector 606 includes at least one of the appliance engagement sensors 520, 522 as will be apparent to a person skilled in the art. The user interface 524 is coupled to the controller 602 and the user interface includes a visual display 608, user controls 610 and a magnetic key decoder 612 each of which is coupled to the controller 602. Other features, such as temperature sensors for monitoring the temperature of respective appliances on the hob 500 are known in the art and are therefore not described.

[0065] Referring to Figure 7 there is illustrated the user interface 524 in accordance with another preferred embodiment of the present invention. As previously mentioned, the user interface 524 includes the visual display 608, user controls 610 and the magnetic key decoder 612. The magnetic key decoder 612 has a recess forming a socket 702 that receives the magnetic key 120. The magnetic key decoder 612 has a plurality of magnetic field sensors 704 and a key positioning interlock 706 for engagement with the user interface positioning interlock 304 of the magnetic key 120.

[0066] When the magnetic key 120 is placed proximal to the magnetic key decoder 612, so that key positioning interlock 706 fully engages with the user interface positioning interlock 304, each of the magnets 206 will be aligned with a respective magnetic field sensor 704 as will be apparent to a person skilled in the art. When so aligned, the magnetic field of each magnet 206 passes through a respective magnetic field sensor 704 and thus, depending on the orientation of each magnet 306, each sensor 704 will either detect a North Pole or South Pole

magnetic field.

[0067] Referring to Figure 8 there is illustrated a schematic circuit diagram of a sensor circuit 800 that forms part of the magnetic key decoder 612 in accordance with a preferred embodiment of the present invention. The sensor circuit 800 includes a constant current source 802 coupled to a positive supply rail -e.V and supplying a voltage input to a positive supply input of the magnetic field sensor 704. This sensor 704 is a Hall Effect sensor with a reference supply input coupled to ground GND. The sensor 704 has two outputs N and S, the N output is coupled to a non-inverting input of an operational amplifier 804 and the S output is coupled to an inverting input of the operational amplifier 804. The N output is also coupled to ground GND through a pull-down resistor Ri, whereas the S output is coupled to the positive supply rail ÷V through a pull-up resistor R2. The positive supply rail +V and a negative supply rail -V are coupled to power supply inputs of the operational amplifier 804 which has an output that therefore swings between +V and -V.

[0068] When there is no magnetic field sensed by the magnetic field sensor 704 the voltage at the inverting input is pulled towards the positive supply rail +V and the voltage at the negative supply rail -V is pulled towards ground GND. Consequently, the voltage at the output of the operational amplifier 804 will be -V until a North Pole of a magnetic field is sensed by the magnetic field sensor 704.

[0069] When considering the embodiment of the above cooking hob 500, the magnetic key decoder 612 for one of the cooking rings 504 has 5 sensor circuits 800 that can each provide output values of logic 1 (+V) or logic 0 (-V).

When there is no magnetic key 120 placed proximal to the magnetic key decoder 612 the output logic values are all logic 0 and provide a 5 bit code of 00000 indicating that no action is required (no cooking appliance requires heating).

Thus since there are 5 magnetic field sensors 704, detecting the magnetic field polarity of a respective aligned magnet 206, the magnetic key decoder 612 can detect and distinguish 31 magnetic field codes MC (the 00000 code is not included as this also indicates no magnetic key 120 inserted into the magnetic key decoder 612).

[0070] Referring to Figure 9 there is illustrated a top plan view of a cooking appliance 900 in accordance with a further preferred embodiment of the present invention. The cooking appliance 900 includes a cooking vessel 902 containing a chamber (not illustrated) and a cover 916, with a handle 918, for enclosing or sealing the chamber. There is ridge in the form of a flange 908 protruding from the vessel 902 and there is an appliance positioning interlock 910 in the form of a recess or slot in a base 912 of the cooking appliance 900. More specifically, the appliance positioning interlock 910 is integral with the flange 908 in this embodiment.

[0071] The cooking appliance 900 also has handles 914 and a magnetic key 920 that is similar to the magnetic key 120 with the exception that the user interface positioning interlock 304 is replaced with a user interface positioning interlock 924 protruding from a side surface of the housing of the magnetic key 920. Thus the user interface positioning interlock 924 is a protruding track which can engage with a complementary slot CS in either the handle 918 or the recess 702 of the magnetic key decoder 612 as and when required. The appliance 900 can be used on the cooking hob 500 (with appropriately positioned actuators for the appliance engagement sensors 520, 522) in a similar fashion the appliance as will be apparent to a person skilled in the art. When using this embodiment, the magnetic key decoder 612 is configured to receive the magnetic key 920 so that it has the complementary slot CS for engaging the user interface positioning interlock 924 thereby ensuring alignment of each of the magnets 206 with a respective magnetic field sensor 704. The appliance 900 has a ferrous based inductive heating member (not illustrated) in the base and the appliance 900 can be used on the cooking hob 500 in a similar fashion the appliance 100 as will be apparent to a person skilled in the art.

[0072] From the above it will be apparent that the present invention allows for a set of cooking appliances SCA formed from, for instance, appliances similar to the cooking appliances 100 or 900. The set of cooking appliances SCA can comprise up to 31 such appliances where the characteristic represented by the magnetic field code MC uniquely identifies each of the appliances from the other appliances in the set of cooking appliances SCA. For example, a first cooking appliance in the set of cooking appliances SCA may have a magnetic key 120 with a magnetic field code from the 5 magnets 206 of SSSSN which is decoded by the magnet decoder 612 as 00001 which may identify the characteristic CH of the cooking appliance 100 as a shallow frying pan. As another example, a second cooking appliance in the set of cooking appliances SCA may have a magnetic key 120 with a magnetic field code MC from the 5 magnets 206 of SSSNS which is decoded by the magnetic key decoder 612 as 00010 which may identify the characteristic CH of the cooking appliance 100 as a deep frying pan.

The full set of magnetic field codes, decoded logic values by the magnetic key decoder 612 and the meaning of the logic values as determined by the controller 602 is shown in table 1 below.

[0073] In table 1 magnetic field codes NSSNN to NNNNN have yet to be assigned a characteristic, however, when required a characteristic of a new appliance can be programmed into the cooking hob 500 by use of a USB memory stick or by any other appropriate means. The characteristics Ch typically, directly or indirectly, identifies the type of cooking appliance 100 and relates to a cooking profile of the cooking appliance 100. The characteristic is therefore used by the controller 602 to control the power output of a driver 604 that powers the inductive coil 510 of the hob 500.

Magnetic field code MC Decoded logic values Characteristic CH 55555 00000 No appliance present SSSSN 00001 Shallow fryer SSSNS 00010 Deep fryer SSSNN 00011 Egg Boiler SSNSS 00100 Steamer SSNSN 00101 SousVidecooker SSNNS 00110 Boiling Pan SSNNN 00111 Steamer SNSSS 01000 Barbeque SNSSN 01001 Griller SNSNS 01010 Toaster SNSNN 01011 Slow Cooking Oven SNNSS 01100 Fast Cooking Oven SNNSN 01101 BainMarie SNNNS 01110 Blanching cooker SNNNN 01111 Simmering pan NSSSS 10000 Egg Poacher NSSSN 10001 Kettle NSSNS 10010 Coffee Percolator NSSNN to NNNNN 10011 to 11111 Undesignated Table 1 magnetic field codes decoded logic values and their decoded cooking characteristics.

[0074] Referring to Figure 10 there is illustrated a schematic block diagram of a cooking hob circuit 1000 in accordance with another preferred embodiment of the present invention. The cooking hob circuit 1000 is part of the cooking hob 500, however the sensors 704 are replaced with switches 1014 having actuators 1016. The cooking hob circuit 600 includes the inductive coil or coils 510 coupled to the output of a driver 604. The controller 602 is coupled to the driver 604 and the appliance detector 606 has an output (or outputs) coupled to the controller 602. The appliance detector 606 includes at least one of the appliance engagement sensors 520, 522 and the user interface 524 is coupled to the controller 602. Furthermore, the user interface includes a visual display 608, user controls 610 and a key decoder 1012 (which includes the switches 1014) each of which is coupled to the controller 602.

[0075] Referring to Figure 11 there is illustrated the user interface 524 in accordance with another preferred embodiment of the present invention. As previously mentioned, the user interface 524 includes the visual display 608, user controls 610 and the key decoder 1012. The key decoder 1012 has a recess forming a socket 1102 that receives a key as described later. The socket 1102 has a base 1110 configured with switch actuator accommodating indentations or slots 1104 that accommodate the actuators 1016 of the switches 1014. The key decoder 1012 has a key positioning interlock 1106 for engagement with a suitably shaped and positioned user interface positioning interlock of an appropriate key as described later.

[0076] Referring to Figure 12 there is illustrated the user interface 524 in accordance with a further preferred embodiment of the present invention. As previously mentioned, the user interface 524 includes the visual display 608, user controls 610 and the key decoder 1012. The key decoder 1012 has a recess forming a socket 1202 that receives a key as described later. The socket 1202 has a side surface 1210 configured with switch actuator accommodating indentations or slots 1204 that accommodate the actuators 1016 of the switches 1014. The key decoder 1012 also has a key positioning interlock 1206 (recess) for engagement with a suitably shaped and positioned user interface positioning interlock of an appropriate key as described later.

[0077] Referring to Figure 13 there is illustrated an underside plan view of a key 1300 in accordance with a further preferred embodiment of the present invention. In this embodiment, the key 1300 has a user interface positioning interlock in the form of a protruding track 1302. There is a plurality of switch engaging regions 1306. These switch engaging regions 1306 provide a code that identifies at least one characteristic of an associated cooking appliance to which the key 1300 can be mounted typically by engagement with a handle as described above with reference to, for instance, cooking appliance 100 or 900.

The code is provided by protruding and non-protruding areas of the switch engaging regions 1306 relative to the protruding track 1302, where the protruding areas are indicated by dashed lines. The key 1300 is used in a similar manner to the key 120, and in use engages with the with the socket 1102 key decoder 1012 to actuate one or more of the actuators 1016 when the key positioning interlock 1106 accommodates the protruding track 1302.

[0078] In operation, when the key 1300 engages the key decoder 1012 a code is provided to the controller 602, the code being indicative of a characteristic of a cooking appliance associated with the key 1300. More specifically, the actuators 1016 are selectively actuated by engagement with protruding areas of the engaging regions 1306. In this regard, the switches 1014 may be either biased as normally open or normally closed and the actuators 1016 may be of the ball-bearing type as will be apparent to a person skilled in the art.

Thus, the switches 1014 can be selectively actuated to provide the code by selective engagement of the actuators 1016 with the switch engaging regions 1306. The code can be used in a similar fashion as described above with reference to table 1 in which the output values from the switches are either a logic 1 or logic zero.

[0079] Referring to Figure 14 there is illustrated an underside plan view of a key 1400 in accordance with another further preferred embodiment of the present invention. In this embodiment, the key 1400 has a user interface positioning interlock 1404 that is a recess having an outline resembling a key and configured to engage with the key positioning interlock 1402. There is a plurality of switch engaging regions 1406. These switch engaging regions 1406 provide a code that identifies at least one characteristic of an associated cooking appliance to which the key 1400 can be mounted typically by engagement with a handle as described above with reference to, for instance, cooking appliance 100 or 900.

The code is provided by protruding and non-protruding areas of the switch engaging regions 1406 relative to the key positioning interlock 1402, where the non-recessed areas are indicated by dashed lines. The key 1400 is used in a similar manner to the key 120, and in use engages with the socket 1202 of key decoder 1012 to actuate one or more of the actuators 1016 when the key positioning interlock 1206 accommodates the key positioning interlock 1402.

[0080] In operation, when the key 1400 engages the key decoder 1012 a code is provided to the controller 602, the code being indicative of a characteristic of a cooking appliance associated with the key 1400. More specifically, the actuators 1016 are selectively actuated by engagement with protruding areas of the engaging regions 1406. In this regard, the switches 1014 may be either biased as normally open or normally closed and the actuators 1016 may be of the ball-bearing type as will be apparent to a person skilled in the art. Thus, the switches 1014 can be selectively actuated to provide the code by selective engagement of the actuators 1016 with the switch engaging regions 1406.

Again, the code can be used in a similar fashion as described above with reference to table 1 in which the output values from the switches are either a logic 1 or logic zero.

[0081] Referring to Figure 15 there is a flow diagram illustrating a method 1500 of determining a characteristic of a cooking appliance seated on the cooking hob 400 in accordance with a preferred embodiment of the present invention. The method 1500 is performed by the circuitry 600 associated with the cooking hob 500 and will be described, by way of example only, with reference to cooking appliance 100 and magnetic key 126. The method 1500 includes, at a detecting block 1510, a process of detecting the cooking 100 appliance seated on the cooking hob 500. This occurs when the appliance positioning interlock operatively couples with the appliance positioning interlock engagement member 506 to thereby position the cooking appliance 100 on the cooking hob 500 ready for use over one of the coils 510. The detecting is complete when the appliance engagement sensors 520 and 522 are actuated to provide a detection signal. The sensors 420, 422 in one embodiment may, however, be used to switch on the cooking hob 500 on as will be apparent to a person skilled in the art.

[0082] At a decoding block 1520 the method 1500 perform a process of decoding the magnetic field code MC to identify a characteristic CH of a cooking appliance 100 seated on the cooking hob 500. This magnetic field code MC is the code provided by the magnetic fields supplied from the plurality of magnets 206 associated with the magnetic key 120 when it is inserted in the correct orientation (as determined for instance by the user interface positioning interlock 304 engaging with the key positioning interlock 706). It should be noted that when the cooking hob circuit 1000 and key 1300 or 1400 are used by the method 1500, the code MC is not a magnetic field code. The characteristic CH is determined from table 1, which is stored in a memory of the controller 602, and the method 1500, at a controlling block 1530, performs a controlling the power output of driver 604.

The controlling is dependent on the characteristic Ch which can be: the type of appliance; the type of cooking provided by the appliance; the required cooking profile of the appliance; a default cooking time for the appliance; or the required inductive power to be supplied to the appliance (the power output requirement of the driver 604).

[0083] If the characteristic Ch is a cooking profile, the controller 602 determines that the characteristic Ch provided from the binary code from the magnet key decoder 612 is a cooking profile identifier. For example, if the decoded logic value is 00011 then the characteristic CH is an egg boiler which has a specific cooking profile and thus the driver 604 is set to provide a suitable power output to heat the ferrous based inductive heating member 130. In some embodiments the controlling can be such that the driver 604 provides power for a pre-defined time, or a pre-defined time once the egg boiler has reached a required temperature, measured by a temperature sensor (such sensors are a well know feature of induction hobs). The method 1500 then ends at an end block 1540.

[0084] It should be noted that although the embodiments illustrate the key as a plug engaging a socket of the decoder, it will be apparent to a person skilled in the art that the key may also be as socket engaging a plug portion of the decoder. Also, in some embodiments the slots or indentations of the decoder may not be necessary (depending on the configuration of the switch engaging regions of the associated key) or can be replaced with protruding areas.

Similarly, the protruding and non-protruding areas of the key can be slots and not slotted areas as will be apparent to a person skilled in the art.

[0085] Advantageously the present invention allows for a characteristic CH of the cooking appliance 100 to be communicated to the induction hob or cooking hob 500 without the need for radio transmitters or transceivers. The characteristic CH is communicated by the magnets 206 to the user interface 524 of the hob 500. These magnets 206 are relatively robust permanent magnets whose magnetic fields are not normally permanently damage or affected by water when the appliance is washed in a washing bowl or even when washed in a dishwashing machine. Once the CH is communicated the cooking hob 500 heats the appliance and the cooking profile is displayed on the visual display 608. A user can thus place a cooking appliance 100 on the cooking hob 500 so that it engages the appliance positioning interlock engagement member and view the display 608 to check the automatically initiated cooking setting. The user can then take their time clean or dry their hands (after preparing the food being cooked) before making any adjustments to the cooking setting by use of the controls 610.

Claims

Claims 1. A cooking appliance for use on a cooking hob, the appliance comprising: a cooking vessel containing a chamber therein; and a key associated with the appliance, the key having plurality of switch engaging regions providing a code that identifies at least one characteristic of the cooking appliance.
2. The cooking appliance, as claimed in claim 1, wherein the key is releaseably mountable to the cooking appliance.
3. The cooking appliance, as claimed in claim 2, wherein the key is releaseably mountable to a handle of the cooking appliance.
4. The cooking appliance, as claimed in claim 1, wherein the cooking appliance has a cover for covering the chamber and wherein a handle of the cover has a recess for complementary engagement with the key.
5. The cooking appliance, as claimed in any one of the preceding claims, wherein the key has a user interface positioning interlock.
6. The cooking appliance, as claimed in any one of the preceding claims, further including an appliance positioning interlock for operatively coupling with an appliance positioning interlock engagement member of a cooking hob to thereby position the cooking appliance on the cooking hob in a predefined location.
7. The cooking appliance, as claimed in any one of the preceding claims, further including a ferrous based inductive heating member associated with the vessel.
8. The cooking appliance, as claimed in any one of the preceding claims, wherein the vessel includes a base for seating the cooking appliance on a cooking hob.
9. The cooking appliance, as claimed in claim 6, wherein there is ferrous based inductive heating member forming at least part of a base of the vessel.
10. A set of cooking appliances, each of the appliances comprising the appliance as claimed in any one of claims 1 to 9, wherein the code of each key uniquely identifies its associated appliance from the other appliances in the set.
11. A cooking hob comprising: at least one inductive coil; a driver having an output coupled to the inductive coil; a controller coupled to the driver; and a key decoder coupled to the controller, the key decoder comprising a plurality of switches, wherein, in operation, when a key engages with the key decoder, the key decoder provides a code to the controller, the code being indicative of a characteristic of a cooking appliance associated with the key.
12. The cooking hob, as claimed in claim 11, wherein the characteristic of a cooking appliance relates to the type of cooking appliance.
13. The cooking hob, as claimed in claim 11 or 12, wherein the characteristic of the cooking appliance relates to a cooking profile of the app1 i ance.
14. The cooking hob, as claimed in any one of claims 11 to 13, further including an appliance positioning interlock engagement member.
15. The cooking hob, as claimed in claim 14, wherein there is at least one appliance engagement sensor associated with the appliance positioning interlock engagement member.
16. The cooking hob, as claimed in any one of claims 11 to 15, wherein the key decoder has a key positioning interlock for engagement with a user interface positioning interlock of the key.
17. A method of determining a characteristic of a cooking appliance seated on a cooking hob, the method being performed by circuitry associated with the cooking hob, and the method including: decoding a code to identify a characteristic of a cooking appliance associated with a key, wherein the code is provided by switch engaging region on the key; and controlling a power output of a driver coupled to an inductive coil of the hob, the controlling being dependent on the characteristic.
18. The method, as claimed in claim 17, including a prior step of detecting the cooking appliance seated on the cooking hob.
19. The method, as claimed in claim 17 or claim 18, wherein the cooking appliance is the appliance as claimed in any one of claims 1 to 9.
20. The method as claimed in any one of claims 17 to 19, wherein the cooking hob is the cooking bob as claimed in any one of claims 11 to 16.
21. The method as claimed in any one of claims 17 to 20, wherein the characteristic of a cooking appliance is a cooking profile identifier.
22. The method as claimed in claim 21, wherein the cooking profile identifier indicates a power output requirement of the driver.
23. A key decoder, the key decoder comprising a plurality switches, wherein, in operation, when a key engages with the key decoder, the key decoder provides a code indicative of a characteristic of a cooking appliance associated with the key.
24. A cooking appliance substantially as described herein with reference to the accompanying drawings.
25. A cooking hob substantially as described herein with reference to the accompanying drawings.
26. A method substantially as described herein with reference to the accompanying drawings.
27. A set of cooking appliances as described herein with reference to the accompanying drawings.