Proximity control device and household appliance equipped with proximity control device

Abstract

A capacitive proximity control device (28) for a household washing machine (10) or other household appliance is proposed. In some embodiments, the proximity control device comprises two planar sensor electrodes (34, 36) arranged at a spatial distance from each other on a door (20) of the washing machine. An electronic component is connected to the two sensor electrodes, the electronic component being adapted to generate an electrical sensor signal associated with each of the two sensor electrodes, the electrical sensor signal being representative of a change in capacitance associated with the sensor electrode in question. By correlating the two sensor signals, the electronic component is able to determine a proximity operation of the control device. A shielding electrode may be arranged in the spatial region between the two sensor electrodes.

Description

Technical Field

[0001] The present invention relates to a proximity control device and a household appliance equipped with the proximity control device. Background Art

[0002] Household appliances (e.g. machines for washing and / or drying clothes, machines for cleaning dishes, or ovens or cookers for heating and / or cooking food) are often equipped with manually operable control elements by means of which the user can manually control the appliance in question. Such control elements exist, for example, in the form of buttons and dials for controlling the operation of the household appliance, but also, for example, in the form of hinged elements for opening the door of the household appliance.

[0003] The operating principle of a capacitive proximity sensor is that by moving an object into the electric field of an (open-circuit) capacitor, the capacitance of the capacitor changes. This capacitance change can be detected by an electrical oscillator circuit, the oscillation frequency of which changes as a function of the capacitor capacitance. By evaluating the oscillation frequency, it is thus possible to detect the approach of an object to the proximity sensor. A proximity sensor can be used, for example, as a proximity switch for detecting an approaching hand or part of a hand of a user and is therefore a possible way to implement a control element for a household appliance.

[0004] Many household appliances have an appliance housing whose housing walls are at least partially metallic and therefore electrically conductive. The presence of a metallic wall in the electric field region of a capacitive proximity sensor influences the electric field of the sensor. Furthermore, vibrations of the housing wall can cause a change in the relative distance between the housing wall and the active capacitor electrode of the proximity sensor. This can cause a change in the capacitance of the proximity sensor, which the evaluation electronics can falsely detect as an approaching object, even if no object is approaching the proximity sensor. Summary of the invention

[0005] An object of the present invention is to provide a proximity control device which allows reliable detection of a user's proximity control gesture in an operating environment of a home appliance and thus reliable control of the home appliance.

[0006] To achieve this objective, the present invention provides a proximity control device for household appliances, the proximity control device comprising: a pair of planar sensor electrodes arranged at a mutual spatial distance; and an electronic component connected to the two sensor electrodes, wherein the electronic component is configured to generate an electrical sensor signal in association with each sensor electrode in the pair of sensor electrodes, and determine the proximity operation of the control device by mutual correlation of the two sensor signals, wherein the electrical sensor signal represents a change in capacitance associated with the corresponding sensor electrode.

[0007] According to the invention, each of a pair of sensor electrodes forms a capacitor electrode of a plate-type capacitor. For each of the two sensor electrodes, a sensor signal is generated by an electronic component, for example by means of a suitable oscillator circuit, which sensor signal represents the change in capacitance of the plate-type capacitor in question. The sensor signal can be, for example, an analog current or voltage signal; alternatively, it can be a digital signal, the signal value of which digital representation represents the capacitor capacitance or a parameter derived therefrom (e.g., the oscillation frequency of the oscillator circuit). A constant potential of a few volts (e.g., a potential between about 1.8 V and about 5 V) can be applied to the two sensor electrodes, wherein it is conceivable that the same potential or a different potential is applied to each of the two sensor electrodes.

[0008] Although the two sensor electrodes are at a certain spatial distance from each other, at least in some embodiments, they are arranged close enough to each other so that when a manual proximity control gesture is correctly performed (e.g., when a user's finger or other part of the hand is moved in an appropriate manner closer to a designated control surface of the proximity control device to operate it), the two sensor signals show a signal curve reflecting the control gesture. In these embodiments, information about the proximity control gesture should therefore be contained in the two sensor signals, for example, in the signal magnitude or / and in the time signal curve. However, the information about the proximity control gesture can be contained in two sensor signals with different characteristics (i.e., for example, with different intensities or / and with different time patterns).

[0009] In some exemplary embodiments, it can be provided that one of the sensor electrodes is arranged spatially closer to the control surface of the proximity control device than another of the sensor electrodes. By means of such a relative arrangement of the sensor electrodes with respect to the control surface, an operating gesture can be reflected, for example, in a signal change in the same direction of the two sensor signals, wherein, however, the signal amplitude of the sensor signal of one sensor electrode is significantly greater than the corresponding amplitude of the sensor signal of the other sensor electrode. Conversely, it can be provided that the sensor electrode arranged closer to the control surface is simultaneously arranged farther away from a metal part of the household appliance (e.g., from a metal housing wall) than the other sensor electrode, the metal part being considered as a potential electrical interference factor for the sensor signal. As a result, although the vibrations of the metal part are again reflected in the signal changes in the same direction of the two sensor signals, the intensity of these signal changes is significantly weaker in the sensor signal of one sensor electrode than in the sensor signal of the other sensor electrode.

[0010] More generally, the proximity control device can be designed specifically by the shape and mutual spatial position of the sensor electrodes so that proximity control gestures and vibrations near metal components affect the sensor signals significantly differently in each case. For example, if the sensor signal associated with one of the sensor electrodes responds relatively more strongly to a manual control gesture of the user, then one of the sensor electrodes can be used as a "hand electrode" as is, while if the sensor signal associated with another of the sensor electrodes responds relatively more strongly to interference from an electrical appliance, then the other of the sensor electrodes can be used as an "electrical appliance electrode" as is.

[0011] By jointly evaluating the two sensor signals, the electronic component can accordingly determine whether a specific observed signal curve of the sensor signals of the two sensor electrodes is due to a proper control gesture of the user (i.e., a proximity operation) or is merely the result of a disturbing influence (undesirable, but often unavoidable in practice). For example, if a user inadvertently hits a household appliance with his leg or arm, an undesired vibration may occur. In the event of such an unexpected occurrence, the operation of the control device is of course not determined by the electronic component. This should only occur when the electronic component determines that the operation of the control device has actually occurred by considering the sensor signals of the two sensor electrodes together. The correlation of the two sensor signals can include, for example, a qualitative or / and quantitative comparison of the signal magnitudes of the two sensor signals. Alternatively or additionally, the correlation of the two sensor signals can include an analysis of the temporal signal pattern of the sensor signals. For example, it is conceivable that mechanical vibrations cause a series of multiple, relatively short-duration signal peaks (especially in the case of signal sampling of the capacitor capacitance or a parameter derived therefrom, the sampling frequency is less than the vibration frequency and is not a natural divisor of the vibration frequency), while the control gesture performed for the purpose of operation causes a longer-duration but continuous signal increase, that is, the signal curve is "smoother" overall. If these characteristic signal patterns are identifiable (ie characteristic of a specific cause of the capacitance change), they can of course be taken into account in the signal evaluation.

[0012] In order to electrically shield the two sensor electrodes from each other, the proximity control device can have a shielding electrode which in particular has the same planar form and is arranged in the spatial region between the two sensor electrodes.The ground potential of the household appliance or another suitable potential can be applied to the shielding electrode.

[0013] The invention further provides a household appliance comprising: an appliance body having a treatment chamber (e.g., a washing chamber, a drying chamber, a dishwashing chamber, a cooking chamber) formed therein; a door arranged to be movable relative to the appliance body for closing the entrance to the treatment chamber; a proximity control device of the type discussed above; and an electronic control unit adapted to implement a predetermined response based on the determination of the proximity operation of the proximity control device. The household appliance is, for example, a washing machine, a tumble dryer or a washer-dryer. A washer-dryer is understood to be a machine combining the functions of a washing machine and a tumble dryer.

[0014] The predetermined response can be any operation that a user can initiate in the household appliance by a suitable manual proximity control gesture, and in particular an operation that can be performed under electrical control. In some embodiments, the predetermined response includes the automatic opening of a closed door. If the electronic components of the control device detect the proximity operation, the control unit can appropriately control the electronically controllable door opening mechanism of the household appliance, for example, so as to overcome the holding closed force of the mechanical latch of the household appliance and push the door open. In other embodiments, the predetermined response includes another appliance function, such as turning on ("waking up") the household appliance, or starting or stopping the execution of an operating program of the household appliance.

[0015] Moreover, in particular when the proximity control device has the function of opening the door of the household appliance, the sensor electrodes can be arranged on the door. The sensor electrodes can thus be arranged in the region of the circumferential edge of the door, wherein they are configured to be elongated in the circumferential direction of the door and overlap each other. The elongated form of the sensor electrodes allows a relatively large control panel to be formed for the user. In front-loading type laundry treatment appliances (i.e. having a circular door, sometimes designed with a bull's-eye window, arranged on the front side of the machine), the sensor electrodes can extend in an arc-shaped curved manner along the circumference of the door.

[0016] As explained, the proximity control device according to the invention is particularly suitable for installation in places where the household appliance has metallic materials spatially close to the installation location of the control device, which can have an adverse effect on the capacitance of the capacitive sensor in terms of interfering influences. Therefore, some embodiments provide that the sensor electrodes are arranged on a side of the appliance on which the appliance body has a metal housing wall.

[0017] The sensor electrodes can thus be arranged at a position on the door such that when the door is closed, one of the sensor electrodes is arranged closer to the metal housing wall than the other of the sensor electrodes. By this relative arrangement of the sensor electrodes with respect to the metal housing wall, the metal housing wall can have a disturbing influence of different strengths on the sensor signals of the two sensor electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings, in which:

[0019] Figure 1 A front loading type household washing machine according to an exemplary embodiment is schematically shown,

[0020] Figure 2 Shows Figure 1 A magnified detail of a washing machine with the door partially open, and

[0021] Figure 3 yes Figure 1 and Figure 2 A circuit diagram of a proximity control device according to an exemplary embodiment provided in a washing machine of FIG. DETAILED DESCRIPTION

[0022] First, refer to Figure 1 Therein, a washing machine shown in highly schematic form and generally indicated by 10 has a machine body (electrical appliance body) 12, in which a washing chamber for receiving the laundry to be cleaned is formed, which is not in the Figure 1 The washing chamber may be formed in a manner known per se in a washing drum which is rotatably accommodated in a liquid container which is accommodated in the interior of a body casing 14 forming the visible outer surface of the machine body 12. In a front wall 16 of the machine body 12, an access opening 18 leading to the washing chamber is formed. A door 20, usually in the form of a bull's eye door, is mounted on the machine body 12 so as to be pivotable about a vertical pivot and to allow the access opening 18 to be closed. Since the access opening 18 is concealed by the door 20 (depicted as closed), the access opening 18 is not visible in the machine body 12. Figure 1 is only indicated by a dotted line. Figure 1 Not shown in more detail, but usually in Figure 1 In washing machines of the type shown, a bead-like door seal is attached to the front wall 16 around the access opening 18, which seal is compressed when the door 20 is closed, thereby sealing the washing chamber from the outside to prevent water leakage when the door 20 is closed.

[0023] In order to keep the door 20 closed when it is brought into the closed position in which the access opening 18 is closed, the washing machine 10 is equipped with a door latch 22. For example, the door latch 22 is of the pull-latch type, which allows the user to open the door 20 simply by pulling the closed door. In some embodiments, the user must pull the door with sufficient force to overcome the holding closed force of the door latch 22. The holding closed force of the door latch 22 is based on, for example, at least one closing spring (not shown in greater detail), which relaxes when the door 20 is closed and must be put under (increased) tension again in order to open the door latch 22. The relaxation of the closing spring when the door 20 is closed has the effect of pulling the door 20 closed, with the result that the door 20 is pulled tighter against the machine body 12 against the resistance of the door seal. Such a pull-latch type is also called a push-pull latch.

[0024] The washing machine 10 also includes an electrically controlled door opener 24, which provides the function of automatically pushing the closed door 20 open. The door opener 24 and the door latch 22 can be separate, mechanically independent functional units, or they can be combined in a structural unit. Here, automatic means that the user does not have to pull the door 20 or push the door 20 by hand. The activation of the door opener 24 can occur under program control; in the exemplary embodiment considered here, a control panel 25 is additionally arranged on the door 20 (see Figure 2 ), the control panel 25 is the portion of the proximity control device that allows the user to activate the door opener 24 to open the door 20 as he wishes.

[0025] exist Figure 1 2, the door latch 22 and the door opener 24 are shown in close proximity to each other, wherein they are arranged substantially diametrically opposite a hinge point at which a door pivot hinge (not shown in greater detail) is located, by which the door 20 is mounted on the machine body 12. This arrangement of the door latch 22 and the door opener 24 is of course only exemplary and non-limiting. Examples of alternative positions for the door opener 24 are provided by Figure 1 The dashed line at 24 ′ depicts a position in which the door opener is arranged with an angular offset of approximately a quarter of a circle relative to the door latch 22 .

[0026] The door opener 24 is electrically controlled by a control unit, indicated at 26, of the washing machine 10. For example, at the end of an operating cycle of the washing machine 10, the control unit 26 may control the door opener 24 under program control to open the door 20 so that moisture or hot steam can escape from the washing chamber and the clothes in the washing chamber will not mold. When opening the door 20, the door opener 24 must overcome a certain holding force (holding closed force) of the latch 22 that attempts to keep the door 20 closed. Additionally, the door opener 24 may be activated by the user touching the control panel 25 with his hand or moving his hand close enough to the control panel 25 so that the capacitive proximity control device 28 ( Figure 3) detects the proximity operation of the proximity control device 28 to activate. The electrical structure of the proximity control device 28 will be described in detail below. However, first Figure 2 .

[0027] according to Figure 2 , the door 20 is in the form of a bull's eye door with a bull's eye window 30. The bull's eye window 30 is surrounded by an annular window frame 32, which is usually made of plastic material, on which a control panel 25 is arranged. The control panel 25 can be formed by a separate sensor module arranged in the window frame 32; alternatively, it is conceivable that the control panel 25 is only a region of the window frame 32 that is visually emphasized to the user. The main function of the control panel 25 is to define a visually perceptible delimited area, which the user interprets as an area for detecting control gestures by sensors. In the area of ​​the control panel 25, an arrangement of two sensor electrodes 34, 36 (indicated by dotted lines) is accommodated in a hidden manner in the window frame 32, which sensor electrodes are in the form of strips and elongated in the example shown. The sensor electrodes 34, 36 can be mounted, for example, at a distance from each other on a common carrier component (not shown), which is in turn arranged in the window frame 32. The sensor module comprising the carrier component and the two sensor electrodes 34, 36 (and optionally an additional shielding electrode) can thus be prefabricated and installed as a prefabricated module on a household appliance, here a washing machine 10. The carrier component can be formed, for example, by a profiled bar which is curved in an arc according to the circumferential contour of the door 20. Alternatively, a printed circuit board can be used as the carrier component, wherein the conductor track surfaces formed on the printed circuit board can form the sensor electrodes 34, 36.

[0028] In the example shown, the sensor electrodes 34, 36 extend in the circumferential direction of the door 20, wherein their circumferential length is, for example, at least 5 cm or at least 10 cm or at least 15 cm or at least 20 cm. Alternatively, it is conceivable to configure the sensor electrodes 34, 36 in such a way that they are elongated in the radial direction (based on the midpoint of the door 20) and to install them in the door 20.

[0029] The distance between the sensor electrodes 34, 36 is, for example, several millimeters or several centimeters. The sensor electrodes 34, 36 are formed, for example, of a metal foil or a metal sheet of a metal material having sufficient conductivity (for example, aluminum or silver); alternatively, they may be formed of a conductive track on a printed circuit board. The two sensor electrodes 34, 36 may be, for example, in the form of plate-type electrodes, or they may be in the form of special-shaped electrodes having, for example, an L-shape or a C-shape in cross section.

[0030] The sensor electrodes 34, 36 may be mounted in the door 20 such that they overlap. This means that when the door 20 is closed, from the perspective of a user standing in front of the front wall 16 of the washing machine 10, the two sensor electrodes 34, 36 are arranged one behind the other (that is, one in front and the other behind). From such a user's perspective, one of the sensor electrodes 34, 36 (in the Figure 2 In the example shown, sensor electrode 34 is the front electrode, while the other of sensor electrodes 34, 36 (in Figure 2 In the example shown, the sensor electrode 36 is the rear electrode. The front sensor electrode 34 is therefore closer to the imaginary user and, therefore, when the door 20 is closed, the front sensor electrode 34 is at a slightly greater distance from the front wall 16 of the machine body 12 than the rear sensor electrode 36. Assuming that the front wall 16 consists at least mostly of a metallic material, the (interference) influence of the front wall 16 on the electric field generated by the rear sensor electrode 36 is greater than the influence of the front wall 16 on the electric field generated by the front sensor electrode 34. For example, if the user hits the front wall 16 with his knee, vibrations may occur at the front wall 16, which then cause the capacitance in the (open) capacitor formed by the front sensor electrode 34 to change to a lesser extent than the capacitance in the (open) capacitor formed by the rear sensor electrode 36.

[0031] However, a mutual overlap of the sensor electrodes 34, 36 is not necessary. For example, if the door 20 must be expected to be able to swing around a certain axis when closing, the sensor electrodes 34, 36 can be arranged on either side of the axis (e.g., mirror symmetry). The swinging movement of the door 20 will then be reflected in the sensor signals of the two sensor electrodes 34, 36 that have a phase offset relative to each other. On the other hand, a proximity control gesture will have a significantly different effect on the sensor signals of the two sensor electrodes 34, 36. In this way, by considering the sensor signals of both sensor electrodes 34, 36 together, a proximity operation of the control device 28 can be distinguished from, for example, an unintentional or undesired swinging of the door 20.

[0032] Conversely, the front sensor electrode 34 is exposed to a greater extent than the rear sensor electrode 36 to the capacitance change that occurs when the user moves his hand toward the control panel 25 with the intention of opening the closed door 20. By appropriately determining the dimensions of the sensor electrodes 34, 36 and configuring the sensor electrodes 34, 36, it is possible to reliably distinguish between the two cases where the capacitance change is caused by the vibration of the front wall 16 or the capacitance change is caused by the user's hand moving closer to the control panel 25 by considering the two sensor signals, each representing the capacitance change of one of the sensor electrodes 34, 36, respectively.

[0033] exist Figure 2In the example shown, the control panel 25 having two sensor electrodes 34, 36 is disposed approximately at the 3 o'clock position of the door 20. It should be understood that the control panel 25 may alternatively be disposed at other positions along the circumference of the door 20, such as the 6 o'clock position.

[0034] exist Figure 2 In the figure, a latch assembly 38 can also be seen, which is part of the latch 22 and has an insertion opening 40, into which a closing stirrup 42 arranged on the door 20 is inserted when the door 20 is closed. The closing stirrup 42 has a front stirrup web 44, which is gripped by a gripper (not shown in more detail here) contained in the assembly 38 when the door 20 is closed. For example, the latch 22 formed by the latch assembly 38 and the closing stirrup 42 can have a configuration as shown and described in DE 198 37248 A1. The content of this DE specification is incorporated herein by reference in its entirety.

[0035] In the example shown, the door opener 24 includes a button 45 disposed on the machine body 12, which is movable between a retracted position and an advanced position ( Figure 2 ) and when the door 20 is closed, the button 45 is able to push the door 20 open by moving forward to the forward position.

[0036] Now we will refer to Figure 3 . According to the circuit diagram shown therein, a positive DC potential +U1 or +U2 is applied to the sensor electrodes 34, 36. It should be understood that, instead of a positive DC potential, a negative DC potential can be applied to the sensor electrodes 34, 36. The potentials applied to the two sensor electrodes 34, 36 can have the same sign or different signs and can be the same or different in magnitude. The two sensor electrodes 34, 36 are connected to an electronic component 48, which generates an electrical sensor signal in association with each of the sensor electrodes 34, 36, which electrical sensor signal represents a change in the capacitance of the open-circuit plate capacitor formed by the sensor electrodes 34, 36 in question. To this end, the electronic component 48 can include, for example, an RC oscillator circuit associated with each of the sensor electrodes 34, 36 in a manner known per se, wherein the sensor electrode 34 or 36 in question is part of the oscillator circuit capacitor. The electronic component 48 can be arranged on the machine body 12 and connected to the sensor electrodes 34, 36 via a wire (not shown in more detail) which is guided via a pivot hinge of the door 20.

[0037] As fingers or other parts of the hand (from Figure 3As a result of the finger (left side in the illustration of the proximity control device 28) moving toward the proximity control device 28, the capacitance of each capacitor formed by the sensor electrodes 34, 36 changes, wherein in the configuration of the proximity control device 28 shown, the capacitance changes in both capacitors are in the same direction (e.g., become larger as the finger gets closer) and are reflected in the changes in the oscillation frequency of the two oscillator circuits (respectively in the same direction). However, because the sensor electrodes 34, 36 are at different distances from the approaching finger, the extent of the capacitance changes in the two sensor electrodes 34, 36 is different.

[0038] If the front wall 16 starts to vibrate, this may also cause a capacitance change of the two capacitors in the same direction but with different intensities. By evaluating the oscillation behavior of the two oscillator circuits, the electronic component 48 can determine whether the observed oscillation frequency change is caused by a manual control gesture of the user or by a vibration of the front wall 16. Accordingly, the electronic component 48 can detect whether a proper (i.e., manual) proximity operation of the proximity control device 28 has occurred, or whether the intensity or / and time curve or / and other characteristics of the observed oscillation frequency change of the oscillator circuits lead to the conclusion that there is no intentional operation of the proximity control device 28.

[0039] The result of the evaluation can be sent by the electronic component 48 to the control unit 26, which can respond in a defined manner according to the communicated evaluation result (if the proximity operation is communicated). For example, as described, when the proximity operation of the proximity control device 28 is communicated, the control unit 26 can realize the automatic opening of the door 20.

[0040] The proximity control device 28 can additionally have a shielding electrode 50 arranged between the two sensor electrodes 34, 36, which in the example shown is at ground potential. Of course, a potential different from ground potential can be selected for the shielding electrode 50. The shielding electrode 50 is mounted together with the sensor electrodes 34, 36 in the window frame 32 of the door 20 and can be part of the sensor module.

Claims

1. A household appliance comprising: an electrical appliance body having a processing chamber formed therein; a door arranged to be movable relative to the appliance body and used to close the entrance and exit to the treatment chamber; A proximity control device for detecting a proximity control gesture of a user; as well as Electronic control unit, Wherein, the proximity control device comprises: a pair of sensor electrodes arranged at a mutual spatial distance; and an electronic assembly connected to the pair of sensor electrodes, wherein the electronic assembly is configured to generate a sensor signal associated with each of the pair of sensor electrodes and determine a proximity operation of the control device by correlating the two sensor signals, the proximity operation comprising the proximity control gesture, wherein the sensor signal represents a change in capacitance associated with the corresponding sensor electrode, wherein each of the pair of sensor electrodes forms a capacitor electrode of a plate-type capacitor, the capacitor electrodes are arranged sufficiently close to each other so that when the proximity control gesture is correctly performed, the two sensor signals show a signal curve reflecting the control gesture, the pair of sensor electrodes are installed in a door so that the pair of sensor electrodes overlap, so that the pair of sensor electrodes are arranged one after another, and one of the sensor electrodes in the pair of sensor electrodes is arranged to be spatially closer to a control surface of the proximity control device than the other sensor electrode in the pair of sensor electrodes, wherein such relative arrangement of the pair of sensor electrodes with respect to the control surface allows reflecting the operation gesture in signal changes of the two sensor signals in the same direction, wherein the signal amplitude of the sensor signal of one of the sensor electrodes in the pair of sensor electrodes is significantly greater than the corresponding amplitude of the sensor signal of the other sensor electrode in the pair of sensor electrodes, wherein a shielding electrode is in a spatial region between the pair of sensor electrodes, and Wherein the electronic control unit is configured to cause a predetermined response based on a determination of proximity operation of the proximity control device.

2. The household appliance according to claim 1, wherein: The predetermined response includes automatic opening of a closed door.

3. The household appliance according to claim 1, wherein: The sensor electrode is mounted on the door and is in a strip-like elongated form, wherein the pair of sensor electrodes are arranged in a region of a circumferential edge of the door and extend in a circumferential direction of the door or in a radial direction.

4. The household appliance according to claim 1, wherein: The pair of sensor electrodes is arranged on a side of the household appliance, wherein on the side the appliance body has a metal housing wall.

5. The household appliance according to claim 4, wherein: The pair of sensor electrodes are arranged at a position on the door such that when the door is closed, one of the pair of sensor electrodes is arranged closer to the metal housing wall than the other of the pair of sensor electrodes.

6. The household appliance according to claim 1, wherein: The household appliance is one of a washing machine, a tumble dryer and a washer-dryer.

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