DISHWASHER

Description

[0001] The invention relates to a dishwasher with a device container providing a treatment chamber, which has a loading opening for access to the treatment chamber and which can be closed by means of a device door rotatably mounted about a pivot axis, and with a motor device which is in operative connection with the device door and by means of which the device door can be moved from an open position to a closed position that closes the loading opening.

[0002] Household appliances in general, and water-using household appliances in particular, are well known from the prior art, which is why a separate printed reference is not required here. Therefore, reference is made only by way of example to EP 2 636 355 A1, which discloses a household appliance in the specific configuration of a dishwasher.

[0003] A dishwasher of this type has a housing that contains a container, which in turn provides a treatment chamber. In its intended use, this chamber serves to hold items, such as dishes, cutlery, and / or the like, in the case of a dishwasher.

[0004] For user access to the treatment chamber, the appliance container has a loading opening. This opening can be closed by means of an appliance door, the closure of which is typically fluid-tight in the case of a water-bearing household appliance. The appliance door is typically hinged to pivot on the housing, generally about a horizontal pivot axis. Unlike the dishwasher known from EP 2 636 355 A1, a dishwasher of this type has a motor for motorized operation of the appliance door. This motor is operatively connected to the appliance door via a power transmission device, enabling the appliance door to be moved from an open position to a closed position that closes the loading opening.In this case, the device door is typically vertically oriented in the closed position, whereas it is in a horizontal position when the loading opening is fully open.

[0005] Using a motorized closing mechanism for the appliance door offers the user the advantage of simplified operation. Furthermore, remote control of the door is possible, for example, via a mobile device carried by the user. However, a disadvantage is that uncontrolled blockages can occur, for instance, if a dish rack is not fully retracted and prevents the door from closing. In addition, there is a risk that user limbs, especially hands and / or fingers, could unintentionally enter the gap between the door and the appliance housing, posing a safety hazard.

[0006] CN 110887337 A discloses a refrigerator with a device container providing a treatment chamber, which has a loading opening for access to the treatment chamber and can be closed by means of a device door rotatably mounted about a pivot axis. The refrigerator has a motor unit that is operatively connected to the device door and assists in closing the device door.

[0007] EP 3 130 696 A1 discloses a washing machine with a motor device for closing the appliance door, wherein the motor current and the door angle are sensed on the one hand, and both sensor signals are evaluated to achieve improved pinch protection.

[0008] Based on the above, the Taskthe invention to further develop a dishwasher of the generic type in such a way that unwanted blockage positions are avoided during motor-driven closing.

[0009] To Solution The invention proposes a dishwasher device to solve this problem, characterized by a control unit which uses a sensor device to detect the movement of the appliance door as a change in the appliance door position over time when the appliance door is moved from an open position to a closed position and outputs a signal corresponding to the appliance door position as an actual value, which compares the actual value with a predefinable target value using a comparison circuit and switches off the motor device if the actual value deviates from the target value outside a predefinable tolerance window.

[0010] According to the invention, an unintended jamming of the appliance door is reliably prevented by a reliable emergency shutdown of the motor unit when a sensor detects an actual position of the appliance door that deviates from the intended position. Thus, if the appliance door spring is defective and / or a jammed door prevents the intended pivoting movement, the actual position deviates from the intended position. This is detected by the appliance and leads to an automatic emergency shutdown of the appliance door motor unit, resulting in the appliance door being stopped. Such a stopping of the appliance door also provides the particularly important safety advantage of preventing the unintended entrapment and crushing of user limbs in the door gap between the appliance door and the appliance housing.Because if a user holds onto a device door that is in a closing motion and / or inserts user limbs into the closing door gap between the device door and the device housing, the device door becomes blocked, which is detected in the manner described above and ultimately leads to the termination of the rotational movement of the device door by switching off the motor unit.

[0011] In principle, sensing the motor current is a common measure for detecting blockages and, if necessary, stopping the drive by switching off the motor current. In the event of a blockage, the motor current increases significantly, which can be detected and used as a criterion for shutdown. However, for the appliance door of a household appliance, sensing the motor current as a criterion for detecting a blockage is not sufficiently reliable. This is due to several reasons. For example, the appliance door is essentially horizontal in the open position, whereas it is vertically oriented in the closed position. This means that, due to the design, the closing force is much higher at the beginning of a closing movement than when the door is fully closed. Consequently, the motor current decreases during a closing movement due to the design.This makes it difficult to reliably detect a jammed position based solely on motor current. Furthermore, manufacturers typically use the same motor design for different dishwasher models. However, the weight of the door and the door brake settings vary depending on the model, leading to different loads on the motors during normal use. Therefore, specifying the maximum permissible motor current is not possible.

[0012] To overcome this problem, according to the inventive design, no motor current monitoring is carried out, which advantageously enables sensing that is independent of the weight, the preload of the spring of a door brake device and the position of the device door, so that in the event of a blockage a reliable and safe shutdown of the motor device can take place.

[0013] The dishwasher according to the invention has a control unit for this purpose. This control unit in turn has a sensor device, a comparator circuit and a shut-off device.

[0014] The sensor device detects the movement of the appliance door as a change in its position over time when it moves from an open to a closed position. This detection is preferably continuous, but can also occur at suitable discrete intervals. Continuous detection is preferred, however, as it provides a higher level of safety.

[0015] The sensor device sends a signal corresponding to the position of the appliance door as an actual signal to the comparator circuit. The sensor device and the comparator circuit are connected for this purpose via communication technology.

[0016] The comparison circuit compares the actual values ​​transmitted by the sensor to the circuit with predefined target values. This comparison determines whether the appliance door is in its intended position during a closing movement. If the actual values ​​deviate from the target values, i.e., if there is a discrepancy, this means that the appliance door is no longer in its intended position. In this case, a shutdown device stops the appliance door by switching off the motor.

[0017] To accommodate potentially varying environmental influences at the installation site of a dishwasher, the invention incorporates a predefinable tolerance range when comparing actual and target values. Therefore, the motor only shuts down if an actual value deviates from a target value outside this predefinable tolerance window. The size of the tolerance window is preferably adjustable, even retroactively, so that the response of the shutdown device can be readjusted as needed and adapted to any specific conditions at the dishwasher's installation site.

[0018] In contrast to motor current monitoring, the invention proposes sensing the position of the appliance door. An automatic shutdown of the motor unit stops the movement of the appliance door if the determined, actual position of the appliance door deviates from the position expected under normal operating conditions. The inventive design thus focuses on monitoring the position of the appliance door over time during the closing process. Under normal operating conditions, the position values ​​of the appliance door change continuously according to a known movement profile. A blockage of the appliance door results in the position values ​​of the appliance door no longer changing, even though the motor unit continues to receive power. The blockage is detected due to the discrepancy between the actual position values ​​and the position values ​​expected according to the movement profile.In normal use, it makes no difference whether the door jam is caused by a broken door spring or by a foreign object wedged in the door gap. The jamming is detected regardless of the door's weight or whether it is still open or has already moved towards the closed position.

[0019] The use of sensors, including those for position detection, in household appliances is, of course, not unknown in the prior art. For example, EP 2 636 355 A1, mentioned at the beginning, discloses a household appliance with a pivoting door that has a sensor to monitor the functionality of a door spring interacting with the door. For this purpose, the sensor can, for example, detect the tilt angle of the door. As soon as a failure of the door spring is detected, an additional braking device is activated, which is suitable for slowing the movement of the door as it pivots downwards. This prevents the door from moving uncontrollably into the open position.However, it is not possible to detect a blocked position of the device door during a motor-driven transition to the closed position by monitoring the door spring, since a blocked position can typically occur even if the door spring is not defective.

[0020] Furthermore, a dishwasher is known from DE 10 2017 221 258 A1, which has a sensor device arranged on the appliance door for emitting a sensor signal integrated with the door. The dishwasher has a control device that is configured to detect the sensor signal and, depending on the detected sensor signal, to recognize an anomalous door state from a number of predefined, possible anomalous states. However, this state detection does not make it possible to monitor a motor-driven movement of the appliance door into the closed position. This is because the state of the appliance door changes continuously during the closing movement, meaning that even an assignment to predefined anomalous states does not allow any conclusion to be drawn about a possible blockage position of the appliance door. Moreover, the position of the appliance door in which it assumes a possible blockage position does not in itself constitute an anomalous state.The crucial factor for a blocked position is that the motor unit responsible for moving the door into the closed position is still energized; neither the door position nor the energization of the motor unit constitutes an anomalous state in itself. Therefore, it is also not possible to detect a blocked position by selecting an anomalous state from a list of possible anomalous states.

[0021] With the design according to the invention, the fault case of a door blockage can be reliably detected in a simple manner based on position or motion sensors, and a shutdown of the door drive can be ensured regardless of the door weight and the door position over the entire door swing range.

[0022] According to a further feature of the invention, the sensor device includes an acceleration sensor provided by the appliance door. In particular, a three-axis acceleration sensor can be used as such. Such a sensor is usually already installed in an appliance door, so that no additional effort or costs are required to implement the embodiment according to the invention.

[0023] Such a three-axis accelerometer is known in the prior art. It measures accelerations, with the oscillation being proportional to the acceleration. One possible measurement principle for such a sensor is that the sensor capacitively measures the displacement of a reference mass. The displacement of the reference mass is proportional to the acceleration. Such sensors can be designed as microelectromechanical systems (MEMS).

[0024] Instead of an acceleration sensor, in particular a three-axis acceleration sensor, another sensor can also be used, including a combination of several independently operating sensors. The essential aspect of the invention is solely that the sensor device can detect the actual position of the appliance door as described above, thus enabling a comparison between the actual position and a target position. This allows for an emergency shutdown of the motor unit interacting with the appliance door in the event of a blockage and / or a defective door spring. Examples of sensors suitable for this purpose include speed sensors, position sensors, tilt sensors, and / or similar devices.

[0025] According to a further feature of the invention, the household appliance is provided with a signaling device for emitting acoustic and / or optical signals, wherein the signaling device is in communication communication with the shutdown device. This allows a user to be visually and / or acoustically notified of a blocked position of the appliance door. This is particularly useful when the appliance door is operated remotely.

[0026] According to a further feature of the invention, the predefinable tolerance window is adjustable. This allows the response behavior of the shutdown device to be adjusted. In particular, subsequent adjustment is also possible, which enables adaptation to the environmental influences prevailing at the installation location of the household appliance.

[0027] The invention will lead to SolutionIn addition to the above-mentioned task, a method for operating a dishwasher, in particular a dishwasher of the type described above, which has a device container providing a treatment chamber, which has a loading opening for access to the treatment chamber, which can be closed by means of a device door rotatably mounted about a pivot axis, and which has a motor device that is operatively connected to the device door and by means of which the device door can be moved from an open position to a closed position that closes the loading opening, wherein when the device door is moved from an open position to the closed position, the movement of the device door is detected as a change in the position of the device door over time by means of a sensor device and a signal corresponding to the position of the device door is output as an actual value,where the actual value is compared with a predefined target value using a comparison circuit, and where, if the actual value deviates from the target value outside a predefined tolerance window, the motor device is switched off by means of a shutdown device.

[0028] This method according to the invention provides the advantages already described above with reference to the dishwasher according to the invention.

[0029] According to the invention, it is further provided that the tolerance window is selected with a deviation of less than 10%, preferably less than 5%, and even more preferably less than one percent of the target value.

[0030] The tolerance range must be selected to ensure reliable and safe shutdown of the motor. Particularly from a safety perspective, the motor must shut down to prevent injuries to the user due to entrapment. Conversely, the motor should not shut down simply because the actual position of the appliance door differs from the expected position by a few millimeters and / or a few degrees in angle, for example, due to temperature fluctuations and the associated material expansion. Therefore, it is proposed that the tolerance range be defined such that an actual value is still acceptable even if it is slightly above or below the target value, with this range being defined as a percentage of the target value.

[0031] As soon as a deviation of the actual value outside the tolerance range is detected, the motor unit is immediately shut down. Due to inherent system inertia, there may be a time lag between the detection of a deviating actual value and the actual shutdown of the motor unit. However, this time lag should be kept as small as possible.

[0032] The design according to the invention advantageously allows for differentiation in the event of a defect between a blockage of the appliance door on the one hand and a broken door spring on the other. This is because, in the case of a blockage of the appliance door, no further change in the actual value occurs. This is due to the fact that the appliance door no longer moves when blocked, and therefore its actual position no longer changes. From the moment of the blockage, the actual value thus remains unchanged. As soon as a constant actual value can be detected by the sensor device, this is equivalent to the fact that the appliance door is blocked in its movement.

[0033] In the case of a defective door spring, unlike in the case of a blockage, the actual value continues to change. This is because the appliance door is not blocked, meaning movement can still occur. However, since the door spring is defective, the actual value deviates from the target value. The actual value therefore changes and is not constant as in the case of a blockage. Nevertheless, despite the change in the actual value, the expected target value is not reached, which can be interpreted as a defective door spring. The particular advantage of the inventive design lies in the fact that a defective door spring can be detected both at the beginning of door closing and when the door spring breaks during door closing, i.e., after the door has begun to close properly. In both cases, the actual value differs from the target value but is not constant.

[0034] The dishwasher is thus designed to distinguish between a blocked door and a defective or broken door spring. To make this distinction, if the measured actual value characterizing the door position deviates from the target value beyond the tolerance range, the system also records whether the actual value changes over time, i.e., whether the door continues to move in the closing direction, or whether it remains constant. For this purpose, the actual value is recorded at least at time t1 and at a later time t2 and compared.

[0035] To allow for sufficient differentiation between a blocked appliance door and a defective or broken door spring, the time interval Δt between t2 and t1 should preferably be sufficiently long, but not too long, in order to minimize the risk posed by a continuing movement of the appliance door. A suitable value for this interval is preferably between 50 ms and 500 ms, particularly around 250 ms.

[0036] If the actual value does not change between t1 and t2, or if its change remains within a further predefined tolerance range, a blockage of the appliance door is assumed. Otherwise, a defect or breakage of the door spring is assumed. Preferably, at least in the latter case, a corresponding warning signal, for example visual and / or audible, is emitted to alert the user to the defective or broken door spring.

[0037] Further features and advantages of the invention will become apparent from the following description with reference to the figures. These show: Fig. 1 shows a schematic side view of a dishwasher according to the invention with the appliance door in the open position; Fig. 2 shows a schematic side view of a dishwasher according to the invention with the appliance door partially closed; Fig. 3 shows a schematic side view of a dishwasher according to the invention with the appliance door in the closed position; Fig. 4 shows a control device of the dishwasher according to the invention in a schematic block diagram; Fig. 5 shows a schematic diagram of the sensing of a blocked position; Fig. 6 shows a schematic diagram of the sensing of a broken door spring; Fig. 7 shows a schematic diagram of the sensing of a door spring breaking during a pivoting movement of the appliance door; and Fig. 8 shows a schematic diagram of an enlarged section of the diagram. Fig. 7.

[0038] Figure 1 Figure 1 shows a schematic side view of a dishwasher 1. The dishwasher 1 has a housing 2, which contains a container 3, in a manner known per se. The container 3, in turn, provides a treatment chamber 4, which, in its intended use, serves to hold the items to be cleaned. Dishwashing baskets 7, which can be pulled out of or moved into the treatment chamber 4 by the user, serve to hold the items to be cleaned.

[0039] For user access to the treatment chamber 4, the device container 3 has a loading opening 5. The loading opening 5 can be closed in a fluid-tight manner by means of a device door 6 which is rotatable about a pivot axis.

[0040] A door spring 9 is provided for simplified handling of the device door 6. This spring is operatively connected to the device door 6 via a cable 8. The cable 8 is arranged at one end on a pivot lever 10 of the device door 6 and at the other end on the door spring 9.

[0041] With the appliance door 6 in the open position, i.e., in the open position as shown in Figure 1 As shown, the door spring 9 is tensioned. When the device door 6 is moved into the closed position according to Figure 3 The door spring 9 contracts, which assists the closing process, i.e., the movement of the appliance door 6 into the closed position. Conversely, if the appliance door 6 moves from the closed position to Figure 3 into the disclosure after Figure 1As the door 6 is moved, the force of gravity acting on it causes the door spring 9 to be tensioned, simultaneously braking the door 6 in its pivoting motion. This reliably prevents the door 6 from unintentionally slamming hard against a designated stop.

[0042] As the depictions according to the Figures 1 - 3 Furthermore, it can be seen that the cable pulley 8 is guided over two elements, in particular pulleys, namely a deflection pulley 13 and a drive pulley 12. The drive pulley 12 is operatively connected to a motor unit 11 and is driven by it in the intended use. This design makes it possible, if necessary, to also drive the device door 6 by means of the motor unit 11 and to open it from the open position. Figure 1 into the closed position after Figure 3to be transferred. Depending on the design of the drive roller 12, a different power transmission means can be provided instead of a cable 8, such as a toothed belt, in which case the drive roller 12 is designed as a gear for a positive connection with the toothed belt. For the embodiment according to the invention, however, it is not important whether the power transmission means between the device door 6 and the door spring 9 is designed as a cable 8, as a toothed belt or otherwise. The decisive factor is initially only that a motor device 11 is provided which enables a motorized closing process of the device door 6, that is, a transfer of the device door 6 from the open position to the closed position.

[0043] According to the invention, the dishwasher 1 has a control unit 14. The functional structure of the control unit 14 is shown schematically in Figure 4As shown in this illustration, the control unit 14 has a sensor unit 15, a comparator circuit 17, a memory 19 and a shutdown device 22. The sensor unit 15 in turn has an accelerometer 16.

[0044] When the appliance door 6 moves from an open to a closed position, the control unit 14 uses the acceleration sensor 16 of the sensor unit 15 to detect the movement of the appliance door 6 as a change in the appliance door position over time. It then outputs a corresponding signal as an actual value, as indicated by arrow 18. This actual value 18 is transmitted to the comparator circuit 17. This circuit compares the actual value 18 with a predefined target value, which is available to the comparator circuit from the memory 19, as indicated by arrow 20. If the comparison between the actual value and the target value reveals that the actual value 18 deviates from the target value 20 outside a predefined tolerance range, the comparator circuit outputs a signal to the shutdown device 22, as indicated by arrow 21.In accordance with arrow 23, this ensures that the motor device 11 is switched off and, optionally in accordance with arrow 24, that a signaling device 25 is activated, by means of which the switching off of the motor device 11 is indicated acoustically and / or visually to a user.

[0045] As a result, the inventive design allows for a continuous comparison between the actual position of the appliance door 6 and the target position expected according to the known movement profile during the closing movement of the appliance door 6. In the event of a deviation, the motor unit 11 is immediately switched off, leading to an immediate stop in the movement of the appliance door 6. To adapt the response behavior of the switching device 22 to specific conditions that may prevail at the installation location of the dishwasher 1, a tolerance window is provided for the comparison between the actual and target values. This tolerance window can, of course, also be set to zero, in which case even the slightest difference between the actual and target values ​​is sufficient to trigger the switching off of the motor unit 11.

[0046] The Figures 5 , 6 and 7Each shows possible procedural scenarios, each based on a schematic diagram representation.

[0047] Figure 5 The upper diagram shows the door position, while the lower diagram shows the switching state of the motor unit 11. In both diagrams, the dashed line represents the target state and the solid line the actual state.

[0048] Figure 5 This reveals a standard blockage of the appliance door 6, which occurs, for example, if one of the washing baskets 7 is not properly inserted into the treatment chamber 4 and protrudes from the loading opening 5, or if an object and / or a user's limb is located in the door gap between the appliance door 6 and the appliance container 3. At time t0, the door drive, i.e., the motor unit 11, is switched on, and the appliance door 6 begins to open from the open position. Figure 1 into the closed position after Figure 3 to move. During the pivoting movement, the movement of the appliance door 6 is detected, according to the invention, as a change in the appliance door position over time. At time t1, a deviation between the actual position and the target position of the appliance door 6 is detected due to a blockage occurring. This leads to the motor unit 11 being switched off at time t2. The time period between t1 and t2 is determined by the inertia of the overall system and should be as short as possible.

[0049] Figure 6The diagram illustrates the case where the door spring 9 is already defective, for example broken, at the beginning of the closing movement of the appliance door 6. Shortly after the motor unit 11 is switched on at time t0, it is detected that the appliance door 6 is still moving, but along a much flatter curve than expected, as shown by the dotted line. This difference in the movement path of the appliance door 6 is detected by the sensor in the manner already described above, which leads to the motor unit 11 being switched off at time t2.

[0050] Figure 7 This shows the case where the door spring 9 breaks during a closing movement of the device door 6; specifically, after the closing movement starts at time t 0, the door spring 9 breaks at time t 1. The motor unit 11 is switched off in the prescribed manner at time t 2.

[0051] As can be seen from a review of the diagram representations according to the Figures 5 to 8 The design according to the invention makes it possible to distinguish between a blockage of the device door 6 and a breakage of the door spring 9 that interacts with the device door 6 in the event of a defect.

[0052] Fig. 5 As previously explained, this shows a blockage. It is significant that the device door 6 is stopped in its movement from time t 1 due to its blockage. The corresponding actual value 18 therefore no longer changes from time t 1 onwards, i.e., it remains the same.

[0053] In the case of a defective door spring 9, as described in the Figure 6 and 7As shown, the device door 6 continues to move, but deviating from the expected target movement. Accordingly, an actual value profile is established that neither corresponds to the target value profile nor remains constant as in the case of a blockage. Therefore, according to the invention, a distinction can be made between a blockage on the one hand and a defective door spring 9 on the other. This is illustrated in the section view according to... Fig. 8 .

[0054] Out of Fig. 8 This results in a deviation between the actual value and the target value being detected at time t 2. This deviation is recorded as the first comparison value Δ 1.

[0055] At the same time t2, a deviation of an actual value (which has remained constant since time t1) from the target value is determined and recorded as a second comparison value Δ2. The two comparison values ​​differ from each other, with the first comparison value Δ1 being lower than the second comparison value Δ2. Thus, at time t2, a deviation from the target curve, indicating a door spring breakage, is detected. This deviation, in the form of comparison value Δ1, can be distinguished from a blockage of the device door 6 corresponding to the actual curve 2 on the one hand, and from a normal target curve on the other.

[0056] To enable this distinction, the time interval Δt between t 2 and t 1 must be chosen to be sufficiently long, but also not too long, in order to minimize the risk emanating from a continuing movement of the device door 6. A suitable value for this interval is preferably between 50 ms and 500 ms, particularly around 250 ms.

[0057] To further improve the detection of a door spring breakage, it may also be possible to record the course of the actual curve within the period between t 2 and t 1 at several different times. Reference sign

[0058] 1 Dishwasher 2 Housing 3 Appliance container 4 Treatment chamber 5 Loading opening 6 Appliance door 7 Wash basket 8 Cable pull 9 Door spring 10 Linkage lever 11 Motor unit 12 Drive roller 13 Deflection roller 14 Control unit 15 Sensor unit 16 Acceleration sensor 17 Comparative circuit 18 Arrow (actual value) 19 Memory 20 Arrow (setpoint value) 21 Arrow (output signal) 22 Shut-off device 23 Arrow (input signal) 24 Arrow (input signal) 25 Signaling device

Claims

1. Dishwasher comprising an appliance container (3) which provides a treatment chamber (4) and has a loading opening (5) for access to the treatment chamber (4), which opening can be closed by means of an appliance door (6) which is rotatably mounted about a pivot axis, comprising a door spring (9) which is operatively connected to the appliance door (6) via a force transmission means, comprising a motor device (11) which is operatively connected to the appliance door (6) and by means of which the appliance door (6) can be transferred from an open position to a closed position which closes the loading opening (5), and comprising a control device (14) which, together with a sensor device (15), detects the movement of the appliance door (6) as a change in the appliance door position over time when the appliance door (6) is transferred from an open position to the closed position, emits a signal corresponding to the appliance door position as an actual value (18), compares the actual value (18) with a predefinable target value (20) using a comparison circuit (17) and, if the actual value (18) deviates from the target value (20) outside a predefinable tolerance window, switches off the motor device (11) using a switching-off device (22), wherein an actual value at a first time point (t1) and an actual value at a later second time point (t2) are recorded and compared with one another, wherein, if the actual value has not changed between the two time points or its change remains within a further predefinable tolerance window, it is deduced that the appliance door (6) is blocked, and, in other cases, it is deduced that the door spring (9) is defective or broken.

2. Dishwasher according to claim 1, characterised in that the sensor device (15) has an acceleration sensor (16) which is provided by the appliance door (6).

3. Dishwasher according to claim 2, characterised in that the acceleration sensor (16) is a three-axis acceleration sensor.

4. Dishwasher according to any of the preceding claims, characterised by a signalling device (25) for emitting acoustic and / or optical signals, which is in communication connection with the switching-off device (22).

5. Dishwasher according to any of the preceding claims, characterised in that the predefinable tolerance window is adjustable.

6. Method for operating a dishwasher, in particular a dishwasher according to any of the preceding claims, the dishwasher having an appliance container (3) which provides a treatment chamber (4) and has a loading opening (5) for access to the treatment chamber (4), which opening can be closed by means of an appliance door (6) which is rotatably mounted about a pivot axis and has a door spring (9) which is operatively connected to the appliance door (6) via a force transmission means, and further having a motor device (11) which is operatively connected to the appliance door (6) and by means of which the appliance door (6) can be transferred from an open position to a closed position which closes the loading opening (5), in which method the movement of the appliance door (6) as a change in the appliance door position over time is detected by means of a sensor device (15) when the appliance door (6) is transferred from an open position to the closed position and a signal corresponding to the appliance door position is emitted as an actual value (18), in which the actual value (18) is compared with a predefinable target value (20) by means of a comparison circuit (17), and in which, if the actual value (18) deviates from the target value (20) outside a predefinable tolerance window, the motor device (11) is switched off by means of a switching-off device (22), and wherein an actual value at a first time point (t1) and an actual value at a later second time point (t2) are recorded and compared with one another, wherein, if the actual value has not changed between the two time points or its change remains within a further predefinable tolerance window, it is deduced that the appliance door (6) is blocked, and, in other cases, it is deduced that the door spring (9) is defective or broken.

7. Method according to claim 6, characterised in that the tolerance window is selected with a deviation of less than 10%, preferably less than 5%, more preferably less than 1%, of the target value (20).

8. Method according to claim 6 or claim 7, characterised in that if a deviation of the actual value (18) from the target value (20) outside the tolerance window is determined, the motor device (11) is immediately switched off.

9. Method according to any of the preceding claims 6 to 8, characterised in that when the motor device (11) is switched off, an acoustic and / or optical signal is emitted by means of a signalling device (25).

10. Method according to any of the preceding claims 6 to 9, characterised in that the motor device (11) is switched off as soon as a constant actual value (18) is detected by the sensor device (15).

11. Method according to claim 10, characterised in that the period between detecting a constant actual value (18) and switching off the motor device (11) is selected to be less than 500 ms.

12. Method according to any of the preceding claims 6 to 11, characterised in that at a time point (t2), the deviation of the actual value (18) from the target value (20) is determined as a first comparison value Δ1, and the deviation of a constant actual value as of a time point (t1) from the target value (20) is determined as second comparison value (Δ2).

13. Method according to claim 12, characterised in that the period between the first time point (t1) and the second time point (t2) is selected to be less than 500 ms, preferably less than 250 ms.

14. Method according to claim 12 or claim 13, characterised in that the first comparison value (Δ1) is compared with the second comparison value (Δ2), a first comparison value (Δ1) falling below the second comparison value (Δ2) being interpreted as a door spring (9) breaking.