EP3951268B1 - Method for operating a cooking hob - Google Patents

Description

FIELD OF APPLICATION AND STATE OF THE ART

The invention relates to a method for operating a hob with a flat hob plate and heating devices on the hob plate.

It is known to provide so-called touch switches as control elements on the top of hobs with multiple cooking zones in the area of the hob plate, or alternatively to provide electromechanical control elements such as rotary knobs. By means of appropriate markings or signs and symbols printed on or next to the control elements on the hob plate, it is possible to see at a glance which of the multiple cooking zones a control element is assigned to or is intended for its operation. In the case of hobs that are designed in particular together with an oven, where the control elements are not provided on top of or on the hob, but on a front in front of and under the hob, such markings next to the control elements cannot be recognized during normal operation, i.e. when an operator is standing close to the hob. Sometimes something should not be displayed when the hob is switched off and no one is present, because this is then not necessary. This can meet requirements or legal specifications for low energy consumption in standby mode.

From the US 2018 / 0 259 190 A1 A hob with illuminated displays is known. A rotary knob that can be illuminated is provided to adjust the power of a heating device on a hob. This can provide information and operating assistance to an operator.

From the EP 2 914 061 A1 Another hob and a method for operating it are known in which the pot detection is started immediately when an operator approaches the hob. The pot detection then looks for a pot on the hob. The result of the pot detection is shown on a display. The presence of an operator is therefore detected.

TASK AND SOLUTION

The invention is based on the object of creating a method as mentioned above with which problems of the prior art can be avoided and in particular a safe and instinctive operation of a hob as well as its advantageous operation is possible.

This object is achieved by a method having the features of claim 1. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are only explained for the hob itself or only for the method for operating it. However, they should be able to apply to the method independently of this.

The wording of the claims is made part of the description by express reference.

The hob has a flat hob plate and heating devices on this hob plate or underneath. These can be different heating devices, advantageously induction heating coils. It also has an operating device for the hob with operating elements, the operating elements being at least partially manually operable rotary knobs. They can be arranged in particular on a vertical control panel in front of and below the level of the hob plate. Knob display means are provided on at least one rotary knob, advantageously LEDs or lamps, particularly advantageously on the front thereof. At least one display or knob display means can be provided per rotary knob. Partial segments, color gradients or color changes depending on residual heat are also conceivable.

Further operating elements can advantageously be touch switches or touch sensors, as are known, for example, in a capacitive design. The operating device of the hob has at least one such operating element on or under the hob plate. Additionally or alternatively, one or more operating elements can be located on or on the rotary knob, or the rotary knobs themselves form the operating elements of the hob. The hob also has hob display means on or under the hob plate, which are designed to illuminate through the hob plate. They can also be designed in a known way, in particular have LEDs. They can be part of the operating device or be independent.

The hob has pan detection means that are advantageously arranged under the hob plate. There are many known options for this, in particular with sensor means under the hob plate on cooking areas that can inductively or capacitively detect a pot on the cooking area. Induction heating coils are advantageous, as they can also form the aforementioned heating devices, i.e. offer both functions.

The hob has a power supply to supply the heating devices with power, either as simple switches or as power electronics or power semiconductors for induction heating coils. They preferably work with a power level specified by the control device.

Furthermore, the hob has a presence sensor, which is advantageously built into it, for example on or under the hob plate or on an aforementioned control panel. It can also be formed by integrated touch sensors. Alternatively, it can be connected to an associated presence sensor, which is arranged elsewhere outside the hob, for example on an extractor hood or on a cupboard above it, or positioned elsewhere in the environment. Communication can advantageously take place wirelessly.

The hob has a power supply for the operating device, and possibly also for the presence sensor if it is integrated in the hob or is part of it. This can be or have a switching power supply. This power supply advantageously has low energy consumption when the hob is in standby mode, i.e. not in use. The voltage supply and the power supply are designed separately, i.e. by different components or different functional units. They can also be arranged on different circuit boards under certain circumstances.

This means that in standby mode, only the low energy consumption of the power supply for the operating device is used. In cooking mode, the power supply is switched on, which then operates or controls the heating devices and supplies them with power.

In an embodiment of the invention, the at least one presence sensor can be arranged on one of the rotary knobs or directly next to it, advantageously at a distance of less than 10 cm or even less than 5 cm. The advantage of mounting it in this location is that the rotary knob itself or the control panel on which it is arranged is directed into the room and can therefore much better detect the presence of an approaching person.

In a further embodiment of the invention, only a single presence sensor can be provided for the entire hob. This alone should be sufficient to detect the approach of an operator, both at a short distance such as 10 cm to 50 cm and at a long distance such as 1 m to 5 m. If the distance between the operator and the presence sensor is detected to be below a predetermined limit distance, which can in particular be less than 2 m or less than 50 cm, the presence sensor activates the hob display means and/or the toggle display means. For this purpose, it also activates a control of the operating device or the hob accordingly, or this controls it. and evaluates it, wherein the control then activates, in particular illuminates, the toggle display means according to the invention.

A presence sensor can be designed as known from motion detectors, but also capacitively using capacitive sensors, for example. Even the aforementioned capacitive touch switches can form a presence sensor, which can then detect an operator at a relatively short distance such as 3 cm to 20 cm, especially if they bend over the hob when putting a pot on.

In the hob, a circuit board for the hob display means can preferably be provided under the hob plate, on which certain components are arranged. The aforementioned additional control elements can also be arranged here. Particularly preferably, the control of the operating device can be arranged on this circuit board for the hob display means or on a separate circuit board directly behind the rotary knobs. This control can advantageously be the entire hob control, so that no further control is required.

Preferably, the heating devices on the hob plate form defined cooking zones, in particular at least partially per cooking zone. Particularly preferably, at least one rotary knob for power adjustment is assigned to at least one heating device, whereby each heating device can be assigned exactly one separate rotary knob intended only for this heating device.

In an advantageous embodiment, the heating devices can be induction heating coils, wherein preferably these induction heating coils then also form the aforementioned pot detection means, so that they can detect pots inductively.

In the method according to the invention for operating a hob as described above, the hob is operated in a standby mode in which all heating devices and the power supply are switched off, in particular also the pan detection means. Preferably, the hob display means are also switched off. On the other hand, the hob is operated in a cooking mode in which the power supply is switched on and at least one heating device can be supplied with power to heat a pan placed above it, wherein preferably at least one hob display means is also switched on. In any case, the power supply can operate the pan detection means if these are formed by induction heating coils as described above. In the standby mode, the presence sensor is active and is supplied with power from the power supply, which is switched on and activated. This can advantageously be the control elements that have to be active anyway to detect that the hob is switched on, especially if they are touch sensors. In cooking mode, the power supply is then switched on and activated. One of the heating devices can be activated or operated and heat, but it does not have to.

According to the invention, the following steps are carried out. Starting from a hob that is in standby mode, an operator approaches the presence sensor, which is also activated in standby mode. If the operator is less than a limit distance from the presence sensor, in particular less than 2 m or less than 50 cm, the presence sensor activates the toggle display means, and possibly also the hob display means. The power supply can be activated with the pot detection, and after a pot is detected, the display means can be activated. This means that information relating to the hob or the status of the hob can be output to the operator or the information can be displayed to the operator. As an alternative to the previously described detection of pots, information can be displayed, in particular relating to the detected size of the pots, residual heat on a cooking area according to a known hot indicator or the like.

In an embodiment of the invention, the hob can be switched from standby mode to cooking mode, whereupon the pot detection system searches for pots placed on the hob plate. The pot detection means are supplied with power from the power supply. In the case of induction heating coils as pot detection means, it is necessary that the power supply has been switched on. However, they do not actually have to heat, they only have to carry out pot detection. Pots placed on the hob plate and detected by the pot detection system can then be displayed with their corresponding position on the corresponding hob display means and/or knob display means.

If the pan detection system cannot detect any pans on the hob and an operator moves beyond the limit distance from the presence sensor, the hob indicators and/or the knob indicators can be deactivated either immediately or after a predefined waiting time. The power supply can then also be switched off again so that the hob is operated in standby mode again. The pan detection system is then no longer needed.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine Schrägansicht eines erfindungsgemäßen Kochfelds an einem Herd mit mehreren Drehknebeln an einer Vorderblende vor einer Kochfeldplatte,

Fig. 2

einen Schnitt durch die Vorderblende des Kochfelds aus Fig. 1 mit einem Anwesenheitssensor daran,

Fig. 3

eine Draufsicht auf das Kochfeld aus Fig. 1 mit den Kochstellen und verschiedenen Möglichkeiten zur Anzeige und

Fig. 4

eine Darstellung einer Leiterplatte mit der Bedieneinrichtung unter der Kochfeldplatte.

Further advantages and aspects of the invention emerge from the claims and from the description of embodiments of the invention, which are explained below with reference to the figures.

Fig.1

an oblique view of a hob according to the invention on a stove with several rotary knobs on a front panel in front of a hob plate,

Fig.2

a cut through the front panel of the hob Fig.1 with a presence sensor on it,

Fig.3

a top view of the hob Fig.1 with the cooking zones and various options for display and

Fig.4

a representation of a circuit board with the control device under the hob plate.

DETAILED DESCRIPTION OF THE EXAMPLES

In the Fig.1 is an oblique view of a hob 11 on a so-called stove 12, i.e. with an oven underneath, whereby the hob could also be installed alone. The hob 11 has a hob plate 14, for example made of known translucent reddish-brown glass ceramic. Four distributed cooking zones 15a to 15d are provided, as is known from the prior art. Each of the four cooking zones 15a to 15d is formed by an induction heating coil of a corresponding size, which is arranged below the hob plate 14. A pot 16 is placed on the cooking zone 15b at the rear left. For the cooking zone 15c at the rear right in Fig.3 the corresponding induction heating coil 15c' is shown for illustration purposes. It is connected to a power supply 38. A control panel 17 is arranged at the front of the stove 12 or the hob 11 below the level of the hob plate 14. In the right-hand area of the control panel 17 there are four rotary knobs 19a to 19d for the hob 12. Each of the rotary knobs 19a to 19d is assigned to a cooking zone 15a to 15d and thus to the induction heating coil associated with it for operation. In the left area, two rotary knobs 20a and 20b are provided for the functions of the oven arranged under the hob 11. This will not be discussed here.

A presence sensor 27 is arranged between the two groups of rotary knobs 19 and 20. This can be designed, for example, like a conventional motion detector, alternatively it can be designed like a reflex light barrier or as a capacitive presence sensor. Its range or a distance that can serve as a limit distance for the distance to an operator can be between a few centimeters and a few meters, and this can possibly also be adjusted or individually set via a connected control 25. Alternatively, the presence sensor 27 could also be arranged directly on the rotary knob 19b or on one of the rotary knobs 19 or 20. As a further alternative, it can be integrated in the operating unit 34 and preferably use the existing operating elements or sensors or touch sensors.

A connecting cable 13 extends schematically from the rear to the hob 12. It is connected to a left-hand power supply 38, with which the induction heating coils of the hobs 15a to 15d are supplied with power in a known manner. Advantageously, the power supply 38 has a conventional power electronics for induction heating coils. Furthermore, the connecting cable 13 is connected to a voltage supply 40 for the control 25 and above all for an operating device 34. The operating device 34 is provided in the front middle area of the hob plate 14. It has several illuminated operating elements 35, with the Fig.3 a control element 35b is shown and illuminated at the rear left. These control elements 35 are advantageously designed as capacitive touch switches, as is known from the prior art. Furthermore, the power supply 40 also serves to supply the presence sensor 27 and possible further displays or illuminated displays. Such further illuminated displays are, according to one possibility, as illuminated displays 33a in front of the cooking area 15a on the left front in Fig.3 activated. They can represent a locally assigned hot indicator, i.e. signal to an operator that this cooking zone 15a still has a temperature above 40°C or 50°C, as is the case with a normal hot indicator. Such a hot indicator could also be provided as an illuminated display in the area of the operating device 34 and be arranged there for the cooking zone 15a on the left front.

According to another possibility, the light indicators 33b surround the cooking area 15b in the form of a circular segment at a small distance. By lighting up in the Fig.3 they indicate that the induction heating coil as a pot detection means has detected the presence of the pot 16 on it. They do not form a hot indicator but indicate that a pot has been detected. This is also the aforementioned information that represents or illustrates the hob or its status. They could also be provided on the operating device 34. For this purpose, the detection of the pot 16 can be displayed on the left rear control element 35b on the operating device 34 by its illumination, as shown in the Fig.3 shows.

The control 25 is always supplied with power by the power supply 40, even if the hob 12 is switched off or in standby mode. Furthermore, the power supply 40 also supplies the presence sensor 27 with power or voltage so that it always works. If an operator approaches the presence sensor at a distance below a predetermined limit distance, the presence sensor 27 detects this. This limit distance can be less than 2 m or even less than 50 cm. In the present case, the Fig.2 This is a hand 29 of an operator that approaches the presence sensor 27 below the limit distance, for example because it moves towards a rotary knob 19 on the front panel 21. This rotary knob 19 can adjust a conventional power control device 22 by means of a shaft 21, which is connected to the control 25 in order to set a power of one of the cooking zones 15a to 15d or their induction heating coils. The control 25 can then activate different display options. On the one hand, it can activate a knob display means 36 on the front of the rotary knob 19, advantageously implemented by an LED, for Fig.2 shown lights. The knob display means 36 is connected to the control 25 by means of a connecting cable 37 within the rotary knob 19 and within the rotary axis 21, and can therefore be controlled by it. For example, it can be indicated that the presence of the operator or their hand 29 has been detected. Furthermore, with the invention, when the presence of an operator is detected by the presence sensor 27, the hot indicator 33a can also be activated, which was previously deactivated because the hob 12 was switched off in standby mode. This can serve to ensure that the hot indicator of the light indicators 33a does not have to be operated when no operator is nearby. Then there is also no danger of an operator burning or injuring themselves here.

Likewise, the indicator lights 33b on the cooking area 15b could light up to indicate to an operator that the pot 16 has been detected by the cooking area 12. For this purpose, it is then necessary that the control 25 switches on the power supply 38 after detecting the presence of the operator. This is necessary for controlling the induction heating coils on the cooking areas 15a to 15d. The control 25 can now cause the induction heating coils to work as a pot detection device in accordance with their usual pot detection function, which is known from the prior art. The induction heating coil of the cooking area 15b will detect the pot 16, and this is indicated by the light displays 33b. An additional or alternative display of the detected pot 16 can be made on the rotary knob 19b by means of the knob display means 36b, so that this only lights up when a pot 16 was also placed on the cooking area 15b associated with the rotary knob 19b and has been detected.

All of this information, displayed or conveyed by the light indicators 33, 35 and 36, is only activated and thus displayed when the operator has approached the stove 11 or the hob 12 at a distance below the limit distance. The special feature here is that not only is the detection of presence indicated in some way, for example by means of the toggle indicator 36b or the light indicators 33a as a hot indicator, but that the pan detection is started. To do this, as described, the power supply 38 for the induction heating coils must first be switched on so that the induction heating coils can work as a pan detection device. The power supply alone is not sufficient or not designed to operate the induction heating coils as a pan detection device.

In the Fig.2 It is also shown how the power control device 22 is arranged on the same circuit board LP1 as the control 25. All power control devices of the control panel 17 are advantageously arranged on this circuit board LP1, or at least those that belong to one of the groups of rotary knobs 19 or 20. The control 25 can then be connected to the operating device 34 by means of a cable or the like.

The Fig.4 shows an arrangement of the operating device 34 with the illuminated operating elements 35 below the hob plate 14. The operating device 34 is arranged on a circuit board LP2. The control 25 can also be arranged on this, as indicated by the dashed line, and not on the circuit board LP1 of the power control devices 22.

In the idle state after connecting the hob 12 to the connection cable 13, the hob 12 is in standby mode. If the power supply 38 is then switched on, for example by switching on the hob 12 or by operating an ON switch, it is in Cooking mode, into which it has changed from standby mode. In cooking mode, it is not necessary to cook or operate one of the induction heating coils for heating. In the invention, it is also not necessary for the hob 12 to be switched from standby mode to cooking mode after the presence of an operator has been detected by the presence sensor 27. This is only the case if it is considered necessary for certain reasons, or in order to activate the induction heating coils of the cooking zones 15 for the function as a pan detection means.

Claims (12)

1. A method of operating a cooking hob (11), the cooking hob (11) comprising:

   - a flat cooking surface (14) and heating devices on or under the cooking surface (14),

   - an operating device (34) for the cooking hob (11) with operating elements (19, 19b, 20, 35, 35b), the operating elements comprising manually operable rotary knobs (19, 19b, 20) , in particular arranged on a vertical control panel (17) in front of and below the level of the hob plate (14),

   - cooking field display means (33, 33a, 33b, 35, 35b) on the cooking field plate (14), which are designed to be transilluminated through the cooking field plate (14),

   wherein:

   - the control device (34) of the cooking field (11) has at least one control element (19, 19b, 20, 35, 35b) or the rotary knobs (19, 19b, 20) on the cooking field plate (14),

   - the cooking field (11) has pot recognition means,

   - the cooking field (11) has a power supply (38) for supplying power to the heating devices, preferably at a power level pre-set by the operating device (34),

   - the cooking field (11) has a presence sensor (27) or is connected to a presence sensor (27) assigned to it,

   - the cooking field (11) has a power supply (40) for the operating device (34) and for the presence sensor (27),

   - toggle display means (36, 36b) are provided on at least one rotary toggle (19, 19b, 20),

   characterized in that the cooking field (11)

   is operated on the one hand in a standby mode in which all heating devices and the power supply (38) are switched off, preferably also the hob display means (33, 33a, 33b, 35, 35b) are switched off, and

   on the other hand, in a cooking mode in which the power supply (38) is switched on and at least one heating device can be supplied with power for heating a pot (16) placed on it,

   - wherein in the standby mode the presence sensor (27) is active and is supplied with power from the power supply (40), wherein the power supply (40) is switched on and activated,

   - wherein in the cooking mode the power supply (38) is switched on and activated, wherein, starting from a cooking field (11) operated in standby mode, an operator (29) approaches the presence sensor (27) and, when the distance between the operator (29) and the presence sensor (27) is below a limit distance, the presence sensor (27) activates the toggle display means (36, 36b) in order to output information to the operator (29) or to display the information to the operator (29), the information relating to the cooking field (11) or the state of the cooking field (11).
2. Method according to claim 1, characterized in that the limit distance is less than 2 m, preferably less than 50 cm.
3. Method according to claim 1 or 2, characterized in that the cooking zone (11) has a cooking zone display means (33, 33a, 33b, 35, 35b) , wherein at least one cooking zone display means (33, 33a, 33b, 35, 35b) is also switched on in the cooking mode and the pot detection means are active.
4. Method according to one of the preceding claims, characterized in that

   - the cooking field (11) is switched from the standby mode to the cooking mode,

   - the pot detection searches for pots (16) placed on the cooking field plate (14), the pot detection means being supplied with power from the power supply (38),

   - any pots (16) placed on the hob plate (14) and detected by the pot detection means are indicated with their corresponding position on corresponding hob display means (33, 33a, 33b, 35, 35b) and/or knob display means (36, 36b).
5. Method according to one of the preceding claims, characterized in that, in the event that the pot detection system is unable to detect any pots (16) on the hob plate (14) and an operator (29) moves away from the presence sensor (27) again beyond the limit distance, either immediately or after a predefined waiting time, the hob display means (33, 33a, 33b, 35, 35b) and/or the toggle display means (36, 36b) are deactivated and the power supply (38) is switched off again, so that the hob (11) is operated again in standby mode. display means (33, 33a, 33b, 35, 35b) and/or the toggle display means (36, 36b) are deactivated and the power supply (38) is switched off again, so that the cooking field (11) is operated again in the standby mode.
6. Method according to one of the preceding claims, characterized in that, after the cooking zone (11) has been changed from the standby mode to the cooking mode, information is displayed alternatively to detected pots (16), the information relating in particular to the detected size of the pots (16), residual heat or the like.
7. Method according to one of the preceding claims, characterized in that the at least one presence sensor (27) is arranged on one of the rotary knobs (19, 19b, 20).
8. Method according to one of the preceding claims, characterized in that a single presence sensor (27) is provided for the entire cooking field (11).
9. Method according to one of the preceding claims, characterized in that a printed circuit board (LP2) for the hob display means (33, 33a, 33b, 35, 35b) is provided in the hob (11) under the hob plate (14), in particular a control (25) of the operating device (34) is arranged on this printed circuit board (LP2) for the hob display means (33, 33a, 33b, 35, 35b) or on a separate printed circuit board (LP1) directly behind the rotary knobs (19, 19b, 20).
10. Method according to one of the preceding claims, characterized in that the heating devices form defined cooking zones (15) on the cooking-zone plate (14).
11. Method according to claim 10, characterized in that at least one heating device is assigned exactly one rotary knob (19, 19b, 20) for setting the power, preferably each heating device being assigned exactly one single rotary knob (19, 19b, 20) of its own and intended only for this heating device.
12. Method according to one of the preceding claims, characterized in that the heating devices are induction heating coils, the induction heating coils preferably also forming the pot detection means.

Images