Household garage appliance with motorized longitudinally adjustable sensor and method for operating such a household garage appliance

Description

[0001] The invention relates to a household cooking appliance comprising a cooking chamber bounded by a cooking chamber wall, wherein a motor-driven longitudinally movable sensor is provided, which can be moved from a rest position further away from the cooking chamber to a measuring position closer to the cooking chamber, and vice versa. The invention also relates to a corresponding method. The invention is particularly advantageously applicable to cooking appliances with a microwave function, e.g., stand-alone microwave ovens or ovens with a microwave function.

[0002] WO 2015 / 141207 A1 discloses a heating cooker equipped with: an infrared sensor located on the outside of a heating chamber, which uses several infrared detection elements to detect the temperature of an object being heated; and a direction-adjusting motor that can change the direction of the infrared sensor. The heating cooker is configured so that the infrared sensor moves to a temperature-detection position when a temperature is being detected and to a standby position when no temperature is being detected. As a result, it is possible to prevent clouding of the infrared sensor lens and a temperature increase of the infrared sensor itself. For example, it is possible to keep the infrared sensor in a state where it is possible to detect the temperature even immediately after heating with steam.

[0003] US 7,696,454 B2 discloses a cooking device comprising a housing with a burner that heats an object. A first image acquisition device may be provided on one side of the housing, and this device may be configured to capture image information corresponding to a heat source generated by the burner. Additionally, a display may be provided on one side of the housing to show the image information captured by the first image acquisition device.

[0004] EP 0 924 964 A2 discloses a microwave oven. This oven has an infrared sensor for measuring the temperature of food during cooking. The sensor is angled downwards and backwards from the upper front edge of the cooking chamber. A cover protects the sensor when it is not needed for measuring the food temperature.

[0005] DE 10 2017 220 889 A1 discloses an oven, in particular a pyrolytic oven, comprising an oven cavity that defines a cooking chamber, an opening leading through the oven cavity, a sensor device with at least one sensor element arranged on the side of the oven cavity facing away from the cooking chamber and directed through the opening into the oven cavity, and a protective device with at least one additional sensor, wherein the protective device is configured to detect a critical thermal condition of the sensor device by means of the at least one additional sensor and, upon detection of the critical thermal condition, at least one protective measure can be triggered which is suitable for reducing a thermal load on the at least one sensor element of the sensor device.

[0006] DE 10 2017 220 886 A1 discloses an oven comprising an oven tube enclosing a cooking chamber, an outer housing, a sensor device directed into the cooking chamber and arranged in an interior space between the oven tube and the outer housing, and at least one sensor fan for supplying the sensor device with cooling air, wherein the sensor device has a tubular, end-open sensor housing in which at least one sensor element is housed and whose front end face is directed towards the cooking chamber, the sensor device has at least one viewing window arranged between the sensor element and the cooking chamber, a rear end face of the sensor housing serves as an air inlet opening for cooling air, a pressure side of the sensor fan is connected to the rear end face, the sensor housing has a lateral air outlet opening for the cooling air, and a suction side of the sensor fan is connected to a space.which is separated from the sensor unit. The oven is, in particular, a pyrolytic oven.

[0007] WO 2019 / 208527 A1 discloses a heating appliance equipped with: a heating chamber containing an object to be heated; a wall opening, which is an opening provided in a wall of the heating chamber; a support frame provided on the outside of the heating chamber to cover the wall opening; and a camera provided on the support frame such that an imaging surface is directed through the wall opening towards the interior of the heating chamber. Furthermore, the heating appliance is equipped with: a shutter, which can open / close to block or open the imaging surface of the camera, and which is provided between the wall opening and the camera; and a fan that blows an airflow towards the camera and the shutter.In addition, the support frame has an air duct to draw in the airflow blown out by the blower and discharge it through the wall opening, which was directed towards the surface, in the direction of the heating chamber.

[0008] CN 107616719 A discloses a camera structure for an electric household oven comprising an oven control compartment and an oven baking compartment, between which a partition is provided. The partition is provided with a window for photographing the oven baking compartment. The partition is fitted with a window cover that can be opened and closed to seal the window. The upper end of the window cover is screwed to the partition. A movable camera assembly is provided, the camera position of which is aligned with the window, and the camera assembly can be moved within the window.

[0009] WO 2020 / 102538 A1 discloses a camera mechanism that can be mounted next to an opening in a grill. The opening can be covered by a movable opening cover. The camera mechanism can include a camera with a camera lens that can be inserted through the opening to physically touch the movable opening cover and move it out of the way, giving the camera lens an unobstructed view of the food cooking in the grill. After capturing images and / or videos of the food, the camera mechanism can transmit the images and / or videos to a client device, allowing the user to see the food cooking in the grill in real time. After capturing the images and / or videos, the camera lens can be removed from the grill through the opening, allowing the movable opening cover to close the opening in the grill again.In other embodiments, the opening may always be open, i.e., there may be no opening cover, or the opening may be covered by a transparent opening cover to facilitate taking pictures and videos of food in the grill through the opening.

[0010] DE 10 2019 206892 A1 discloses a cooking appliance. This appliance has a cooking chamber bounded by a cooking chamber wall, at least one sensor unit arranged outside the cooking chamber, and an opening in the cooking chamber wall through which at least one property of the cooking chamber can be detected by means of the at least one sensor unit. A motor-movable exchange device is provided outside the cooking chamber, the exchange device is equipped with at least two sensor units for detecting at least one property of the cooking chamber, and the exchange device can be adjusted by motor movement so that one of the sensor units can be moved in front of the opening at any given time.A method is used to operate a cooking appliance, wherein during cooking operation at least one of the sensor units is brought from a standby position to an active position as required by moving the switching device, a measurement is carried out there using this sensor unit and this sensor unit is immediately returned to the standby position after the measurement.

[0011] KR 2016 0069359 A discloses an electric stove and a method for controlling it. According to one aspect, the electric stove comprises a main body that includes a cooking chamber and a compartment for electrical appliances; a door that selectively opens / closes the cooking chamber; a camera module that photographs the interior of the cooking chamber through an opening connected to the cooking chamber and the compartment for electrical appliances via the door opening; a shielding element that selectively shields the opening through the door opening; and a control element that recognizes the material of a container placed in the cooking chamber based on an image photographed by the camera module.

[0012] WO 2019 / 101529 A1 reveals an oven.This includes an oven enclosing a cooking chamber, an outer housing, a sensor device directed into the cooking chamber and arranged in an interior space between the oven and the outer housing, and at least one sensor fan for supplying the sensor device with cooling air, wherein the sensor device has a tubular, end-open sensor housing in which at least one sensor element is housed and whose front end face is directed towards the cooking chamber, the sensor device has at least one viewing window arranged between the sensor element and the cooking chamber, a rear end face of the sensor housing serves as an air inlet opening for cooling air, a pressure side of the sensor fan is connected to the rear end face, the sensor housing has a lateral air outlet opening for the cooling air, and a suction side of the sensor fan is connected to a space that is separated from the space of the sensor device.The oven is specifically a pyrolytic oven.

[0013] WO 2020 / 200969 A1 discloses a household cooking appliance. This appliance has a cooking chamber bounded by a cooking chamber wall and a cooking chamber camera located outside the cooking chamber for capturing images from the cooking chamber through a viewing opening in the cooking chamber wall. The cooking chamber camera is movable between a rest position and a recording position by means of the household cooking appliance. In the recording position, the cooking chamber camera is exposed to a greater thermal temperature within the cooking chamber than in the rest position. The household cooking appliance is configured to move the cooking chamber camera from the rest position to the recording position during operation and to move it back to the rest position after the recording. A method is provided for operating a household cooking appliance.

[0014] It is the TaskThe present invention aims to overcome the disadvantages of the prior art, at least in part, and in particular to provide an inexpensive and robust way to selectively expose a sensor to a cooking chamber and protect it from the influence of the cooking chamber.

[0015] This problem is solved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims and / or the description.

[0016] The problem is solved by a household cooking appliance having a cooking chamber bounded by a cooking chamber wall, wherein A sleeve ("guide sleeve") with a "cooking-chain-side" end opening that opens into or is directed towards the cooking chamber is provided on the cooking chamber wall, at least one sensor is housed in the guide sleeve so as to be longitudinally displaceable by a motor, and the cooking-chain-side end opening can be closed by means of a closing element which, together with the at least one sensor, is movable by a motor, wherein when the at least one sensor is in a rest position further away from the cooking-chain-side end opening, the closing element closes the cooking-chain-side end opening, and when the at least one sensor is in a measuring position closer to the cooking-chain-side end opening, the closing element releases the cooking-chain-side end opening for the at least one sensor.

[0017] In addition, another sleeve ("sensor sleeve") is housed in the guide sleeve in a motor-driven longitudinally displaceable manner, at least one sensor is attached to an end face of the sensor sleeve on the cooking chamber side, and the sensor sleeve is connected to the locking element via a linkage.

[0018] This cooking device offers the advantage of a particularly robust, yet simple and cost-effective way to expose a sensor to either a cooking chamber or a cooking chamber atmosphere, while at least thermally protecting it from the chamber's heat. The sensor and the locking element can be moved between the rest position and the measuring position, or between the closed and open positions, using a single drive mechanism. The use of the guide sleeve provides the further advantage of requiring minimal space outside the installation area.

[0019] Another advantage is that the sensor can be temporarily moved into its measuring position without having to remain there permanently and thus not be exposed to aggressive cooking chamber conditions such as high temperatures, an aggressive atmosphere, etc. This allows the use of sensors that can measure briefly in the measuring position (active position) without damage, but would not be able to withstand the prevailing cooking chamber conditions permanently.

[0020] The sensor sleeve offers the advantage that the sensor sleeve, and thus the sensor itself, can be guided through the guide sleeve particularly easily and reliably. Specifically, the guide sleeve and the sensor sleeve are longitudinally adjustable relative to each other. Another advantage of the sensor sleeve is that a sensor can be attached to it easily and securely, especially when inserted into the end wall facing the cooking chamber. A further advantage is that the sensor's electrical wiring can be easily routed through the sensor sleeve.

[0021] A household cooking appliance can be, for example, an oven, microwave oven, steam oven, or any combination thereof, such as an oven with microwave and / or steam functions. The cooking chamber wall, especially in the case of an oven, can also be referred to as a muffle or oven cavity.

[0022] A sleeve can be understood to be, in particular, a tubular or hollow cylindrical receptacle or housing for the sensor. The sleeve is typically straight (linear longitudinal axis), but can also be curved (curved longitudinal axis). The sleeve can, for example, have a circular, oval, rectangular, or free-form cross-section. A further development is that the guide sleeve has a diameter between 10 mm and 20 mm, particularly between 11 mm and 20 mm, especially between 15 mm and 17 mm, and most notably around 16 mm. A sensor, e.g., an IR sensor, can, for example, have a typical diameter of approximately 10 mm.

[0023] In a further development, the presence of the guide sleeve on the cooking chamber wall can be further defined as a component manufactured separately from the cooking chamber wall, which is inserted into a suitable opening in the cooking chamber wall. The guide sleeve can be flush with the cooking chamber wall, in which case, in particular, the cooking chamber-side end opening of the guide sleeve can be flush with the cooking chamber wall. Alternatively, the guide sleeve can protrude through the cooking chamber wall into the cooking chamber. An advantage of this design is that the guide sleeve and the sensor can be easily connected separately outside the cooking chamber.

[0024] In a further development, the presence of the guide sleeve on the cooking chamber wall can be configured as an outward-facing protrusion of the cooking chamber wall, thus forming part of the cooking chamber wall. An advantage of this development is that it eliminates the need for separate manufacturing and attachment of the guide sleeve to the cooking chamber wall. Furthermore, this design implicitly provides an electrical connection between the guide sleeve and the cooking chamber wall, which is particularly advantageous for microwave ovens, as it simplifies the shielding of microwave radiation in the area of ​​the guide sleeve.

[0025] The fact that the sensor is mounted in the guide sleeve in a motor-driven, longitudinally displaceable manner, specifically means that the sensor can be moved along a longitudinal extension of the guide sleeve by means of a motor. In its measuring position, the sensor can still be located within the guide sleeve (typically near the end opening of the guide sleeve facing the cooking chamber), be flush with the end opening facing the cooking chamber, or even protrude through the end opening facing the cooking chamber into the cooking chamber.

[0026] The fact that the locking element is movable together with the sensor by a motor means, in particular, that the movement of the locking element occurs simultaneously with the movement of the sensor. A further development is that the locking element and the sensor are movable by the same motor. The motor can, for example, be an electric motor.

[0027] The locking element is movable, in particular, between a closed position in which it closes the end opening on the cooking chamber side, especially when it rests against it, and an open position in which it is lifted from the end opening of the guide sleeve on the cooking chamber side. In particular, the movements of the sensor and the locking element are coordinated such that when the sensor is in its rest position, the locking element is in its closed position, and when the sensor is in its measuring position, the locking element is in its open position. The locking element can, for example, be disc-shaped.

[0028] The fact that the locking element "releases" the opening on the front of the cooking chamber "for the sensor" specifically means that, with the opening released, the sensor is enabled to take measurements of the cooking chamber and / or its contents. The sensor can therefore also be referred to as a "cooking chamber sensor." When the locking element is closed, thus blocking the opening on the front of the cooking chamber, the locking element obstructs the sensor, and the sensor cannot take any practically meaningful measurements of the cooking chamber or its contents.

[0029] It is a further development that the at least one sensor includes at least one infrared (IR) sensor, in particular at least one IR sensor measuring in the mid-infrared range (at typical wavelengths between, for example, 3 µm and 50 µm). The fact that the locking element "releases the front opening on the cooking chamber side for the at least one sensor" can, in this case, mean that the locking element is located in a spatial area outside the IR sensor's field of view or occupies only a practically negligible peripheral area of ​​the field of view. This can also be expressed as the open locking element allowing the at least one IR sensor a view into the cooking chamber.

[0030] The at least one IR sensor can then, for example, capture thermal images of the cooking chamber and its contents; with multiple IR sensors, this can be achieved in different spectral ranges. In particular, the at least one IR sensor can be an IR camera sensor that generates pixel-like thermal images. The use of such an openable shutter element is especially advantageous for IR sensors because alternative IR-transparent protective lenses are very expensive and prone to contamination.

[0031] An alternative or additional development option is that the at least one sensor includes at least one sensor sensitive in the visible spectral range ("camera sensor"). The opened shutter element, analogous to the IR sensor, provides a field of view for the at least one camera sensor to capture images from inside the cooking chamber.

[0032] It is an alternative or additional training option that the at least one sensor includes at least one ultrasonic sensor.

[0033] An alternative or additional feature is that the at least one sensor includes at least one sensor designed to determine a property of the atmosphere being measured ("atmosphere sensor"), e.g., an oxygen sensor, a humidity sensor, a sensor for detecting certain chemical substances, etc. Such atmosphere sensors, by their very nature, must come into contact with the medium being measured (the cooking chamber atmosphere), but they do not utilize a direct line of sight. Rather, in this case, it is sufficient that the open locking element is raised far enough from the cooking chamber-side opening that the sensor is exposed to the cooking chamber atmosphere to a practically sufficient degree.

[0034] It is a further development that the sensor sleeve is designed as a rack into which a gear, driven by a motor, engages. This advantageously provides a simple, precise, and robust method for the motorized longitudinal displacement of the sensor sleeve within the guide sleeve. For this purpose, one outer surface of the sensor sleeve can, for example, be designed with a series of teeth.

[0035] Particularly when designed as a rack and pinion, the sensor sleeve can permanently protrude (i.e., also in the measuring position) from a rear end face of the guide sleeve to ensure a constant engagement of the gear in the rack in a simple way.

[0036] In another improved design, the guide sleeve can have an opening through which the gear can engage with the teeth of the sensor sleeve. This allows the sensor sleeve to be made significantly shorter than if it had to protrude from the side of the guide sleeve facing away from the cooking chamber, even in the measuring position. A further advantage is that the drive unit then no longer needs to be located at one end of the guide sleeve, but can be positioned next to it, thus saving space.

[0037] In yet another refinement, the sensor sleeve can have an external thread, allowing the inner sensor sleeve to be linearly displaced by rotating a motor-driven threaded nut that engages this thread. In the simplest case, the drive (motor) can be located at the end of the guide sleeve facing away from the cooking chamber. This could be the case, for example, with a direct drive of the sensor sleeve via a hollow motor shaft (with an internal spindle thread). A more complex, but fundamentally possible, approach would be to drive the sensor sleeve via a threaded nut rotatably mounted on the end of the guide sleeve facing away from the cooking chamber, which in turn could be driven, for example, by a motor pinion via an external toothed ring.

[0038] One embodiment features a hinged flap as the locking element. This advantageously simplifies the process of creating a viewing area for an imaging IR or camera sensor in the measuring position. The hinge axis of the flap can be formed, for example, by the guide sleeve or the cooking chamber. Transmitting the sensor's movement is particularly straightforward when the flap and sensor sleeve are connected via a hinged rod. When the sensor sleeve is moved from its rest position to the measuring position, it opens the flap via the rod. Conversely, when the sensor sleeve is moved from the measuring position to its rest position, it retracts the flap from its open position to the closed position.

[0039] This is a further development in which the locking element is firmly connected to the sensor, particularly the sensor sleeve, and can be moved or moved analogously to the sensor or sensor sleeve. This development is particularly advantageous for non-imaging sensors such as humidity sensors, etc., and is especially easy and robust to implement. To implement this development, the locking element can, for example, be spaced from the cooking chamber-side end face of the sensor sleeve by one or more rods or pins. When the sensor moves from its rest position to its measuring position, the locking element is moved analogously (especially linearly) by the cooking chamber-side opening and thus lifted until an open position located in front of the cooking chamber-side opening is reached.Conversely, when the sensor is moved back from the measuring position to its rest position, the sealing element is placed back onto the opening on the cooking chamber side by a corresponding (especially linear) movement. Such a sealing element can also be called a sealing cover. It can, in particular, be disc-shaped.

[0040] One design feature is that the locking element is made at least partially of a material with poor thermal conductivity. This offers the advantage that, when the sensor is in its resting position and the locking element closes the guide tube against the cooking chamber, the thermal stress on the interior of the guide sleeve containing the sensor is reduced. The locking element can, for example, be made at least partially of plastic.

[0041] This design incorporates a microwave function in the household cooking appliance, and the sealing element is microwave-tight in its overlapping area with the cooking chamber-side opening of the guide sleeve. This prevents microwave radiation from leaking from the cooking chamber through the cooking chamber-side opening into the guide sleeve. This, in turn, reduces the strain on the sensor and can further prevent or reduce the escape of microwave radiation from the cooking chamber. In this case, the sealing element can, for example, be made of metal.

[0042] A further development involves the locking element being partially made of a poorly thermally conductive material and being microwave-tight in its overlapping area with the oven-side end opening of the guide sleeve. This advantageously combines the benefits of thermal shielding and microwave protection. For this development, the locking element can, for example, be metallic on one side – e.g., the side facing the oven (in the closed position) – and made of plastic on the other side – e.g., the side facing the guide sleeve (in the closed position). The metallic side can be formed, for example, by a metallic coating on a plastic base. Alternatively, the locking element can have a sandwich construction consisting of a metallic layer and a highly heat-insulating, non-metallic layer.

[0043] One embodiment of the household cooking appliance features a microwave function, and the guide sleeve is electrically conductive on its outer casing and electrically connected to the cooking chamber wall. This advantageously also achieves microwave tightness of the guide sleeve itself, because the resulting metallic tube (guide sleeve) creates a so-called cut-off effect of a thin tube cross-section, thus preventing microwave leakage radiation from escaping through the guide sleeve. This is particularly true if the (inner) diameter of the guide sleeve is less than 25 mm.

[0044] The guide sleeve, particularly its outer surface, may have holes or recesses to advantageously allow airflow through the guide sleeve, for example, to cool the at least one sensor. A commonly used appliance cooling fan or a dedicated fan can be used to generate the cooling airflow. If the household cooking appliance has a microwave function, it is particularly advantageous if the holes are so small that they do not affect its microwave resistance.

[0045] One embodiment features the locking element in an airtight seal against the oven-chamber-side end opening of the guide sleeve in its rest position. This advantageously achieves a particularly effective seal against steam, preventing airflow from the oven chamber into the guide sleeve even when the locking element is closed. This, in turn, protects the at least one sensor in its rest position from thermal and chemical stress. This embodiment can be implemented, for example, by providing the flap and / or the guide sleeve with a sealing ring or by using a sealing material in the contact area.

[0046] One embodiment includes at least one IR sensor, and an inner surface of the locking element, at least in its overlap area with the guide sleeve, has an emissivity of nearly 1 in the sensor's IR spectral range. This can also be expressed as the locking element being designed as a near-ideal blackbody radiator on its side facing the interior of the guide sleeve (in the closed position), with an emissivity of approximately 1. In its rest position, the IR sensor then at least partially points towards this overlap area. This embodiment has the advantage that the IR sensor can be calibrated at a known temperature of the cooking chamber, since it is assumed that the temperature at the overlap area corresponds to the temperature of the cooking chamber, and the IR sensor can thus correlate the wavelength of the IR light measured at the overlap area with the cooking chamber temperature.It can be calibrated. The cooking chamber temperature can be measured, for example, using a dedicated cooking chamber temperature sensor, such as a thermocouple or other sensor.

[0047] The problem can also be solved by a method for operating a household cooking appliance as described above. The method can be designed analogously to the household appliance, and vice versa, and offers the same advantages.

[0048] Particularly preferred is a method for operating a household cooking appliance comprising a cooking chamber bounded by a cooking chamber wall, wherein a guide sleeve with a cooking chamber-side end opening opening into the cooking chamber is provided on the cooking chamber wall, a sensor is motor-driven and longitudinally displaceable in the guide sleeve, and the cooking chamber-side end opening can be closed by means of a closing element which is motor-driven together with the sensor, wherein in the method, by actuating a drive motor, the sensor is selectively moved from a rest position further away from the cooking chamber-side end opening to a measuring position closer to the cooking chamber-side end opening, and the closing element is moved from its closed position closing the cooking chamber-side end opening to its open position releasing the cooking chamber-side end opening for the sensor, or vice versa.

[0049] It is a further development that at least one sensor is moved into its measuring position during a treatment process or operation of the household appliance, such as a cooking process, in order to take measurements from the cooking chamber (images, thermal images, ultrasound measurement, humidity measurement, etc.).

[0050] It is a further development that the at least one sensor is moved into its measuring position to take measurements from the cooking chamber and, after a measurement or measuring phase, is moved back to its resting position ("intermittent measurement"). This can be advantageous for protecting the at least one sensor, especially when continuous measurement is not necessary.

[0051] It is a further development that the at least one sensor is moved into its measuring position to take measurements from the cooking chamber and is only moved back to its rest position when at least one predefined criterion, indicating that the sensor could be dirty and / or damaged, is met. For example, the at least one sensor can be moved back to its rest position when the cooking chamber temperature reaches or exceeds a certain threshold.

[0052] It is an embodiment in which the sensor is an IR sensor, an inner surface of the locking element has an emissivity of nearly 1 at least in its overlap area with an interior of the guide sleeve in the spectral range of the sensor, and the cooking chamber temperature is sensed by means of a temperature probe, wherein in the method the sensor is calibrated by comparing the thermal radiation sensed on the inner surface of the locking element and the cooking chamber temperature sensed by means of the temperature probe.

[0053] Specifically, for example, the typically homogeneous temperature distribution in the cooking chamber of a switched-off cooking appliance can be used to calibrate the IR sensor, since in this state the cooking chamber temperature measured by the appliance's temperature sensor corresponds very well with the temperature of adjacent components and thus with the temperature of the locking element. Additionally or alternatively, calibration at higher temperatures is also possible, especially if, for example, a mapping table is available that shows the relationship between the cooking chamber temperature and the temperature of the locking element.

[0054] The properties, features and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in conjunction with the drawings. Fig. 1 shows, as a sectional view in side view, components of a household cooking appliance with the sensor in its measuring position; and Fig. 2 shows, as a sectional view in side view, the components of the household cooking appliance made of Fig. 1 with the sensor in its resting position

[0055] Fig. 1The diagram shows a sectional view in side view of components of a household cooking appliance 1 in the form of a combined oven / microwave oven. Specifically, a muffle 2 is shown, which also serves as the cooking chamber wall 3 of a cooking chamber 4. In a ceiling 3a of the cooking chamber wall 3, a dome 5 for receiving a rotating antenna (not shown) is shown, through which microwaves can be fed into the cooking chamber 4. The dome 5 is separated from the actual cooking chamber 4 by a microwave-permeable cover 6. The cooking chamber 4 also contains at least one heating element 7 for heating the cooking chamber 4 and / or for irradiating the food with heat radiation; in this case, a tubular resistance heating element for top heating and / or grilling, arranged on the ceiling.

[0056] A guide sleeve 8 in the form of a straight, circular cylindrical tube is arranged on the ceiling 3a. This sleeve has a flange-like bent rim 10 at its end opening 9 on the cooking chamber side, which opens into the cooking chamber 4. The guide sleeve 8 is a separately manufactured component that has been inserted from the cooking chamber 4 through an opening or hole in the ceiling 3a such that the rim 10 rests against the inside of the ceiling 3a and is airtightly attached there, e.g., by laser welding. In this case, the rim 10 is angled relative to a longitudinal axis of the guide sleeve 8, so that the mounted guide sleeve 8 is at an angle. This improves visibility into the cooking chamber 4 when the guide sleeve 8 is positioned off-center.

[0057] If the guide sleeve 8 is made of metal, it is electrically connected to the also metallic oven wall 8. The diameter of the guide sleeve 8 is approximately 16 mm, and therefore, in its metallic or metal-coated version, it is impervious to microwaves with frequency ranges typical for household microwave ovens, around 915 MHz or 2.45 GHz. The guide sleeve 8 may have small holes or recesses, which do not affect its microwave resistance. This allows for better cooling of the at least one sensor 14, as the cooling airflow from a commonly installed appliance cooling fan (not shown) can be used to generate an airflow through the guide sleeve 8.

[0058] A sensor sleeve 11 is mounted in the guide sleeve 8 so that it can be moved longitudinally by a motor. This is achieved by forming an outer surface of the sensor sleeve 11 with a longitudinally extending row of teeth 12, and by providing a recess 20 in the outer surface or side wall of the guide sleeve 8 through which the row of teeth 12 is exposed. The household cooking appliance 1 also has an electric motor 21, onto whose drive shaft a gear 22 is mounted, the toothed ring of which in turn engages with the row of teeth 12 through the recess 20. By actuating the electric motor 21 and rotating the gear 22 accordingly, the sensor sleeve 11 can be moved between two end positions, as indicated by the double arrow P1: between the measuring position shown and a position described in more detail below. Fig. 2 shown resting position.

[0059] A sensor, for example an IR sensor 14, is inserted on the cooking chamber-side end face 13 of the sensor sleeve 11. In the version shown, this sensor is flush with the cooking chamber-side end face 13. The IR sensor 14 is thus also mounted in the guide sleeve 8 and is motor-driven for longitudinal movement. As shown for the measuring position, it can be moved out of the guide sleeve 8, either outside its rest position or by being moved out of it.

[0060] The IR sensor can, for example, have a diameter of approximately 10 mm, which then also corresponds to the inner diameter of the tubular sensor sleeve 11. A rod 15 is rotatably connected to the sensor sleeve 11 and projects outwards from the sensor sleeve on the cooking chamber side. At its other end, the rod 15 is connected to a hinged flap 17, which is pivotally attached to the edge 10 via a hinge 16, thus allowing the hinged flap 17 to move, as indicated by the double arrow P2. More precisely, the other end of the rod 15 is rotatably connected to a projection 19 that extends upwards in an overlap area 18 of the hinged flap 17.

[0061] In the illustrated measuring position of the IR sensor 14, the locking flap 17 is pivoted away from the end face 13 of the sensor sleeve 11 by means of the rod 15 to such an extent that the opening on the cooking chamber side is clear for the IR sensor 14 and the locking flap 17 is no longer within the field of view F of the IR sensor 14. The IR sensor 14 can therefore acquire a thermal image of the cooking chamber 4 without obstruction from the locking flap 17.

[0062] When the sensor sleeve 11 is retracted from the measuring position into the guide sleeve 8, the IR sensor 14 is also retracted into the guide sleeve 8 until it reaches a rest position further away from the cooking chamber 4. The IR sensor 14 and the closing flap 17 can therefore be moved together by the electric motor.

[0063] Generally, the sensor sleeve 11 can be moved between the operating and rest positions. It is a further development that the sensor sleeve 11 can also be moved to intermediate positions.

[0064] When the sensor sleeve 11 is inserted into the guide sleeve 8, it pulls the rod 15 into the guide sleeve 8, causing the closing flap 17 to pivot around the hinge 16 towards the oven-side end opening 9. This closing movement can continue until the IR sensor 14 is in its rest position, at which point the closing flap 17 is in its closed position, covering the oven-side end opening 9. The covering area 18 then points into the guide sleeve 8. The projection 19 is also located in the guide sleeve 8.

[0065] The closing flap 17 or the rim 10 can be designed to provide a seal, e.g. by including a sealing ring (not shown) or a sealing coating. This reliably prevents air from entering the guide sleeve 8 in the rest position.

[0066] The closing flap 17 can be disc-shaped and, for example, its side facing the cooking chamber 4 ("outer side") in the rest position can be metallic (e.g., coated or lined), while its inner side facing the guide sleeve 8 in the rest position, which corresponds to the cover area 18, can be made of a poorly thermally conductive material, e.g., plastic, ceramic, micanite, or similar. The metallic layer also effectively prevents microwaves from entering the guide sleeve 8.

[0067] In particular, the cover area 18 can have a surface with an emissivity close to 1. In this case, the cover area 18, which is located in the field of view of the IR sensor 14 in its rest position, can be used to calibrate the IR sensor 14 in its rest position.

[0068] During a cooking cycle, the household cooking appliance 1 can be operated as follows, for example: In one variant, thermal images are taken practically continuously or at short intervals from the cooking chamber 4 and thus also of the food being cooked in the cooking chamber 4. For this purpose, at the beginning of the cooking cycle, the electric motor is actuated so that the sensor sleeve 11 is moved forward from its retracted rest position towards the cooking chamber 4 and, via the rod 15, pushes open the previously closed locking flap 17, so that it lifts off the end opening 9 on the cooking chamber side. The sensor sleeve 11 is moved until the Fig. 1The measurement position shown is reached. In this position, the IR sensor 14 captures the thermal images. The sensor sleeve 11 is retracted into the guide sleeve 8 in the opposite direction, particularly if (a) the IR sensor 14 is no longer needed, e.g., because the cooking process is complete, and / or (b) the IR sensor 14 could be damaged, e.g., because the cooking chamber temperature has reached or exceeded a predetermined threshold. In the rest position, the IR sensor 14 is protected from the cooking chamber 4 by the cover flap 17, specifically from microwaves, thermal radiation, and the cooking chamber atmosphere. Furthermore, in the rest position, the IR sensor 14 is relatively far from the cooking chamber 4, thus also reducing its thermal load.

[0069] In another variant, thermal images are taken at longer intervals. For this, the IR sensor 14 only needs to be moved from its resting position to its measuring position for each image and is then moved back to its resting position after the image has been taken.

[0070] Of course, the present invention is not limited to the embodiment shown.

[0071] In general, "ein", "eine", etc. can be understood to mean singular or plural, especially in the sense of "at least one" or "one or more", etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

[0072] A numerical specification can also include exactly the specified number as well as a normal tolerance range, unless this is explicitly excluded. Reference symbol list

[0073] 1 Household cooking appliance 2 Muffle 3 Cooking chamber wall 3a Ceiling 4 Cooking chamber 5 Dome 6 Cover 7 Heating element 8 Guide sleeve 9 Cooking chamber end opening 10 Edge 11 Sensor sleeve 12 Rack and pinion 13 End face 14 IR sensor 15 Rod 16 Hinge 17 Closing flap 18 Coverage area 19 Projection 20 Recess in the guide sleeve 21 Electric motor 22 Gear P1 Double arrow P2 Double arrow

Claims

1. Household cooking appliance (1) comprising a cooking compartment (3) delimited by a cooking compartment wall (4), wherein - a guide sleeve (8) is provided on the cooking compartment wall (3) with a cooking compartment-side end opening (9) which opens into the cooking compartment (4), - at least one sensor (14) is housed in the guide sleeve (8) so as to be longitudinally movable by motor power and - the cooking compartment-side end opening (9) can be closed by means of a closure element (17) which can be moved by motor power together with the at least one sensor (14), wherein - when the at least one sensor (14) is located in a rest position further away from the cooking compartment-side end opening (9), the closure element (17) closes the cooking compartment-side end opening (9), and - when the at least one sensor (14) is located in a measuring position nearer to the cooking compartment-side end opening (9), the closure element (17) clears the cooking compartment-side end opening (9) for the at least one sensor (14), and wherein - a sensor sleeve (11) is housed in the guide sleeve (8) so as to be longitudinally movable by motor power, the at least one sensor (14) is attached to a cooking compartment-side end face of the sensor sleeve (11), and the sensor sleeve (11) is connected via a rod system (15) to the closure element (17).

2. Household cooking appliance (1) according to claim 1, wherein the sensor sleeve (11) is designed as a toothed rack (12) in which a gear wheel (22) engages, the gear wheel being able to be driven by a motor (21).

3. Household cooking appliance (1) according to claim 2, wherein the guide sleeve (8) has a through-hole (20), through which the gear wheel (22) can engage in the toothing of the sensor sleeve (11).

4. Household cooking appliance (1) according to one of claims 2 or 3, wherein the sensor sleeve (11) protrudes permanently from a rear front surface of the guide sleeve (8).

5. Household cooking appliance (1) according to claim 1, wherein the sensor sleeve has an external thread so that by rotating a threaded nut, which is driven by motor power and which engages in the external thread, the inner sensor sleeve can be moved in a linear manner.

6. Household cooking appliance (1) according to one of the preceding claims, wherein the closure element (17) is a pivotable closure flap.

7. Household cooking appliance (1) according to one of the preceding claims, wherein the household cooking appliance (1) has a microwave function.

8. Household cooking appliance (1) according to claim 7, wherein the closure element (17) partially consists of a poor thermally conductive material and is configured so as to be microwave-tight in its overlapping region (18) with the cooking compartment-side end opening (9) of the guide sleeve (8), in particular by way of provision of a metallic layer.

9. Household cooking appliance (1) according to one of claims 7 to 8, wherein the guide sleeve (8) is configured so as to be electrically conductive on the lateral surface thereof and is electrically connected to the cooking compartment wall (3).

10. Household cooking appliance (1) according to claim 9, wherein an inner diameter of the guide sleeve (8) is small enough, in particular smaller than 25 mm, that a cut-off effect from microwave radiation is achieved.

11. Household cooking appliance according to one of the preceding claims, wherein in the household cooking appliance (1), an appliance cooling fan or a dedicated fan for generating a cooling air flow is built-in, the guide sleeve (8) is arranged in the region of the cooling air flow and the guide sleeve (8), in particular the lateral surface, has holes to facilitate a cooling air flow through the guide sleeve (8).

12. Household cooking appliance (1) according to one of the preceding claims, wherein - the guide sleeve (8) is configured in the form of a separately produced rectilinear, circular cylindrical tube, which has an edge (10) which is bent over in the manner of a flange on its cooking compartment-side end opening (9) which opens into the cooking compartment (4), - the guide sleeve (8) has been passed from the cooking compartment (4) through a through-hole in the cooking compartment wall (3) such that the edge (10) bears on the inner face against the cooking compartment wall (3) and has been fastened thereto in an airtight manner, - the rod system (15) is rotatably connected to the sensor sleeve (11) in the form of one rod, which protrudes relative to the sensor sleeve (11) on the cooking compartment side, - on its other end, the rod system (15) is connected to a closure element (17) in the form of a closure flap which is pivotably attached to the edge (10) via a hinge (16), in particular such that the rod system (15) is rotatably connected on its other end to a projection (19) protruding vertically in an overlapping region (18) of the closure element (17).

13. Household cooking appliance (1) according to one of the preceding claims, wherein in the rest position, the closure element (17) is positioned in an airtight manner on the cooking compartment-side end opening (9) of the guide sleeve (8), in that the closure element (17) and / or the guide sleeve (8) has a sealing ring or is provided with a sealing material in the contact region.

14. Household cooking appliance (1) according to one of the preceding claims, wherein - the sensor (14) is an IR sensor (14) and an inner surface of the closure element (17) has an emissivity of approximately 1 in the IR spectral range of the sensor (14) at least in its overlapping region (18), - household cooking appliance (1) additionally has a temperature probe, which is configured to detect a cooking compartment temperature of the cooking compartment (4), and - household cooking appliance (1) is configured to calibrate the sensor (14) by comparing the thermal radiation detected on the inner surface of the closure element (17) and the cooking compartment temperature detected by means of the temperature probe.

15. Method for operating a household cooking appliance (1) according to one of preceding claims, in which, by way of actuating a drive motor (21), on a selective basis - the sensor sleeve (11) with the sensor (14) is moved out of a rest position further away from the cooking compartment-side end opening (9) to a measuring position nearer to the cooking compartment-side end opening (9), and at the same time the closure element (17) is moved out of its closed position closing the cooking compartment-side end opening (9) and is pressed into its open position clearing the cooking compartment-side end opening (9) for the sensor (14) via the rod (15), - or vice versa, the sensor sleeve (11) is moved out of the measuring position into the rest position and at the same time the closure element (17) pulls back from its open position into the closed position.