SURFACE CLEANING MACHINE WITH TANK DEVICE FOR DIRT FLUID

Description

[0001] The invention relates to a surface cleaning machine, comprising a cleaning head with at least one cleaning roller unit which is driven for a rotational movement, a tank device for dirty fluid and a probe device for determining a filling level of the tank device for dirty fluid, wherein the probe device is designed as an electrode device and has a first electrode and a second electrode spaced from the first electrode, which protrude into a receiving space of the tank device for dirty fluid.

[0002] US 2006 / 0190133 A1 discloses an autonomous floor cleaning robot with a chassis. The chassis carries a supply of cleaning fluid and a receptacle for materials collected from a surface to be cleaned.

[0003] WO 2019 / 048449 A1 discloses a self-propelled and self-steering floor cleaning device with a cleaning liquid container and a dirty liquid container.

[0004] Surface cleaning machines are known from applications WO 2016 / 058901 A1, WO 2016 / 058856 A1, WO 2017 / 063663 A1, WO 2016 / 058879 A1, and WO 2016 / 058956 A1. A surface cleaning machine is also known from WO 2016 / 058907 A1.

[0005] From US 4,875,246 a portable floor cleaning device is known which has a roller driven by an electric motor.

[0006] From DE 20 2009 013 434 U1 a device for wet cleaning floors with a brush which can be rotated about a rotation axis is known.

[0007] A cleaning machine is known from CN 201 197 698 Y.

[0008] US 6,026,529 discloses a device for cleaning floors or other hard surfaces.

[0009] From WO 2005 / 087075 A1 a floor cleaning machine with a handle is known which is pivotably arranged on a base.

[0010] Another floor cleaning machine is known from WO 2015 / 086083 A1.

[0011] A hard floor cleaning device is known from US 3,789,449.

[0012] CN 107007215 A discloses a floor cleaning robot.

[0013] DE 20 2018 104 772 U1 discloses a dirty water collection mechanism and dirty water detection mechanism and a cleaning device.

[0014] The invention is based on the object of providing a surface cleaning machine of the type mentioned above, which can be operated in a simple and safe manner.

[0015] This object is achieved according to the invention in the surface cleaning machine mentioned at the outset in that the first electrode and the second electrode are firmly connected to a holder for the tank device for dirty fluid, wherein the tank device for dirty fluid is detachable from the holder.

[0016] The sensor device detects whether the dirty fluid tank is filled with dirty fluid. This prevents the surface cleaning machine from continuing to operate once the tank reaches a certain fill level, or it can indicate to the operator (particularly visually and / or acoustically) that the dirty fluid tank needs to be emptied.

[0017] This prevents the tank system for dirty fluid from becoming overfilled and resulting in insufficient cleaning results; it prevents the tank system from overflowing, which could result in dirty fluid being released back onto a surface to be cleaned.

[0018] Furthermore, emptying the tank system is made easier for the operator, as the specific fill level is determined in such a way that the tank system for dirty fluid can be easily emptied. In particular, the tank system for dirty fluid can be removed without the dirty fluid spilling out, provided the specific fill level is not exceeded.

[0019] Furthermore, possible damage to a floor covering as a surface to be cleaned due to leaking liquid or puddle formation is avoided.

[0020] It is particularly advantageous if the probe device is designed as a resistance measuring device. Such a probe device can be easily designed, controlled, and evaluated. With a resistance measuring device, it is easy to check whether dirty fluid is present between the probes of the probe device. This can be done via current measurement or resistance measurement. For example, if a certain fill level is reached and there is liquid (dirty fluid) between the probes of the probe device, a current can flow between the probes via the dirty fluid. This manifests itself in a change in resistance compared to the case where there is no liquid between the probes. This change in resistance is detectable and indicates that a certain fill level has been reached.This specific fill level is, in turn, determined by the relative arrangement of the probes on the tank system. The probe system, designed as a resistance measuring device, can be implemented simply and cost-effectively. The corresponding probe system can be implemented with minimal susceptibility. Susceptibility to contact with dirt in the contaminated fluid can also be minimized.

[0021] The probe device is designed as an electrode device. The probes are then, in particular, electrodes between which a voltage is applied or to which a current is applied. Resistance can be easily determined, with a change in resistance being a measure that a certain filling level has been reached.

[0022] The electrode device comprises at least one pair of electrodes comprising a first electrode and a second electrode spaced apart from the first electrode, which extend into a receiving space of the tank device for dirty fluid. The arrangement of the electrodes determines which specific filling level is to be detected. If a plurality of electrode pairs comprising (each) a first electrode and a second electrode are provided, which are arranged at different heights, then different specific filling levels can also be determined.

[0023] The first electrode and the second electrode are firmly connected to a holder for the dirty fluid tank, with the dirty fluid tank being detachable from the holder. This allows for a simple implementation of a probe device that does not need to be detachable from the dirty fluid tank. This results in a simple design.

[0024] It is advantageously provided that the electrode device is arranged and configured such that a specific filling level of the tank device for dirty fluid can be detected. If electrodes of the electrode device protrude into the receiving space of the tank device at a specific height, and electrode pairs are formed, then a specific filling level can be detected by fluid passing between the electrodes of an electrode pair.

[0025] In one embodiment, a direct current or direct voltage is applied to the electrode device. A base signal is applied, and the fill level can then be determined from a reaction signal. In particular, a direct voltage is applied to the electrodes of an electrode pair. If there is no liquid between the electrodes of the electrode pair, then no current can flow between them. Ideally, the resistance can be considered infinite. If there is liquid (dirty fluid) between the electrodes of an electrode pair, then a current can flow via the liquid. This reduces the resistance. This creates a corresponding reaction signal, which can be determined.From the corresponding change in the response signal (corresponding first to an idealized resistance of infinity and then to a finite resistance) it can be detected whether a liquid level in the tank device for dirty fluid has reached the corresponding electrode pair.

[0026] It is advantageous if the probe device is connected to an evaluation device in a signal-effective manner, in particular to at least one of the following: the evaluation device controls a display device and / or a transmitter; the evaluation device initiates a warning signal for the display device and / or the transmitter when the reaching of a certain filling level is detected; the evaluation device checks a filling level of the tank device for dirty fluid by means of a resistance determination; the evaluation device controls the probe device, in particular with a direct current signal or direct voltage signal; the evaluation device comprises a filter device which checks temporal changes in the signals of the probe device, wherein in particular the filter device is designed such that a temporary sloshing of dirty fluid in the tank device for dirty fluid can be detected;The evaluation device switches off a drive for the at least one cleaning roller unit and / or a conveyance or conveyability of cleaning fluid if a certain filling level is detected at the tank device for dirty fluid; the evaluation device prevents a rotation drive of the at least one cleaning roller unit and / or a suction operation when a certain filling level is detected when the surface cleaning machine is put into operation.

[0027] By controlling a display device via the evaluation device, the operator can be shown a fill level and, in particular, a warning signal can be issued. If a transmitter is controlled accordingly, the fill level of the dirty fluid tank system can be displayed, for example, on a remote control or a mobile device, and, in particular, a warning signal can be issued via this mobile device.

[0028] The evaluation device preferably checks the fill level of the dirty fluid tank device by measuring resistance. It is preferably provided that the evaluation device controls the probe device, in particular with a direct current signal or a direct voltage signal. Using a corresponding response signal, the evaluation device can then detect the fill level and, in particular, whether a certain fill level has been reached.

[0029] The evaluation device preferably comprises a filter device, and in particular an electronic filter device, which checks temporal changes in the signals from the probe device. This makes it possible to determine whether or not there is a relatively short-term sloshing of dirty fluid in the dirty fluid tank device. This makes it possible to filter out short-term sloshing in order to reliably determine the fill level. In particular, the evaluation device is designed such that operation of the surface cleaning machine is switched off when a certain fill level is detected for the dirty fluid tank device and / or that start-up is prevented upon corresponding detection. This prevents, in particular, overfilling of the dirty fluid tank device.The dirty fluid tank system can be emptied ergonomically, as a maximum fill level (the specified fill level) cannot be exceeded. Potential damage to floor coverings due to leaking dirty fluid or puddle formation is avoided.

[0030] It is advantageous if the indicator is arranged on a handle, via which the cleaning head can be guided by an operator, and / or if the indicator is arranged on the cleaning head. This allows an operator to easily determine the fill level of the dirty fluid tank. A warning signal can be easily recognized by an operator. In particular, a visual and / or acoustic signal is displayed on the indicator.

[0031] In one embodiment, a first cleaning roller unit and a second roller unit spaced apart from the first cleaning roller unit are provided, wherein the tank device for dirty fluid is positioned between the first cleaning roller unit and the second roller unit. In particular, the cleaning head is supported on a surface to be cleaned via the first cleaning roller unit and the second roller unit. This allows the position of the tank device for dirty fluid to be kept relatively stable. The sloshing of dirty fluid in the tank device for dirty fluid is kept to a minimum.

[0032] In one embodiment, the second roller unit is a second cleaning roller unit or a sweeping roller unit, with counter-rotation of the first cleaning roller unit and the second roller unit being provided. In principle, it is also possible for the second roller unit to be a pure support unit without a cleaning function.

[0033] In one embodiment, a cover wall is provided, which is connected to the cleaning head and covers the tank device for the dirty fluid. This results in a simple structural design. In particular, the tank device for the dirty fluid can then be inserted into the cleaning head from below, or from the side, and in particular between the first cleaning roller unit and the second roller unit.

[0034] It is advantageous if the electrodes of the probe device are arranged on the cover wall and, in particular, are firmly connected to the cleaning head. This allows the implementation of a probe device that does not need to be detachably connected to the tank device for the dirty fluid. For example, the cover wall itself then forms a cover for the tank device, or a further cover is provided for the tank device. This cover is then provided with appropriate feedthroughs for the electrodes.

[0035] It is advantageous if electrodes of the probe device protrude in a direction transverse to a plane from the cover wall into a receiving space of the tank device for dirty fluid, wherein a first rotation axis of the first rotating roller unit and a second roller axis of the second roller unit lie in this plane. Said plane is, in particular, parallel to an enveloping plane of the cover wall. This results in a simple structural design. The electrodes can be firmly positioned on the cleaning head.

[0036] In an alternative embodiment, the tank device for dirty fluid is detachably mounted on a support rod device on which the cleaning head is located. The support rod device serves, in particular, to enable an operator to operate the surface cleaning machine while standing, with the operator then standing, in particular, on a floor that is to be cleaned with the surface cleaning machine. In particular, the probe device is firmly connected to the support rod device if the tank device for dirty fluid is detachable. Detaching the tank device then means that the probe device does not have to be taken along with the tank device.

[0037] It is also possible for the surface cleaning machine according to the invention to be designed as a self-propelled and self-steering device and in particular as a cleaning robot.

[0038] Furthermore, it is possible for the surface cleaning machine to be designed as a hand-held device, which in particular has a support rod device on which the cleaning head is mounted. In particular, a standing operator, standing on the surface to be cleaned, then operates the hand-held device, with the cleaning head supported by the at least one cleaning roller unit on the surface to be cleaned.

[0039] It is advantageous to provide a moistening device by means of which the at least one cleaning roller unit and / or a surface to be cleaned can be exposed to cleaning fluid, wherein the moistening device has a tank device for cleaning fluid. This allows for improved dirt removal.

[0040] It is advantageous if a flow area for cleaning liquid is provided, through which cleaning liquid, which is provided by the tank device for cleaning liquid, flows when supplied to the at least one cleaning roller unit and / or to a surface to be cleaned.

[0041] A sensor device is arranged at the flow area to detect the presence of cleaning fluid in the flow area.

[0042] By checking whether cleaning fluid is present in the flow area, it is possible to determine whether the tank system is empty (i.e., no longer contains any cleaning fluid). If the tank system is empty, then there will also be no cleaning fluid in the flow area.

[0043] This makes it easy to monitor the emptying of the cleaning fluid tank. This test can be performed outside the tank. This allows for a simple design of the cleaning fluid tank and the surface cleaning machine. There is no need to make provisions for the sensor device or any part of it to be removable from the surface cleaning machine.

[0044] By locating the sensor device at the flow area, the cleaning fluid tank can be checked regardless of its position. Even sloshing of cleaning fluid in the tank has no effect on the sensor device's check.

[0045] By determining whether the tank for cleaning fluid is empty, it is easy to prevent the surface cleaning machine from being operated without cleaning fluid. This ensures a satisfactory cleaning result. Furthermore, potential damage to a surface covering (such as a floor covering) can be prevented by using corresponding detection results from the sensor device, for example, to shut down the surface cleaning machine, and in particular to drive the at least one cleaning roller unit in rotation.

[0046] It is advantageous if the flow area is formed on a pipe or hose. This allows the corresponding surface cleaning machine to be easily designed.

[0047] In one embodiment, the flow area is arranged below the tank device for cleaning fluid with respect to the direction of gravity during proper operation of the surface cleaning machine. This allows cleaning fluid to be supplied from the tank device, in particular, to the at least one cleaning roller unit and / or the surface to be cleaned in a gravity-driven manner and, in particular, without the need for a pump. In particular, no pump is required.

[0048] For the same reasons, it is advantageous if the flow area is located downstream of a connection for the cleaning fluid tank device, relative to the direction of flow of the cleaning fluid. This allows for a detection test for the filling of the cleaning fluid tank device (at least "digitally" with regard to cleaning fluid or empty tank device). This test can be performed essentially regardless of the position, and sloshing of cleaning fluid in the tank device does not affect the measurement result.

[0049] In a structurally simple embodiment, a holder is provided on which the tank device for cleaning fluid is held, particularly detachably. This allows the tank device for cleaning fluid to be easily positioned on the surface cleaning machine, for example, on a holding rod device or on the cleaning head.

[0050] A structurally simple design is achieved if a connection for the tank device for cleaning fluid is arranged on the holder.

[0051] In particular, it is provided that a flow through the flow area is coupled to a rotary drive of the at least one cleaning roller unit and / or that the flow area is connected upstream of a valve device for conveying cleaning fluid to the at least one cleaning roller unit and / or to the surface to be cleaned. If, for example, the surface cleaning machine is switched on, i.e. the rotary drive is switched on, then the flow area can be flowed through, for example by opening a valve device, in order to provide cleaning fluid to the at least one cleaning roller unit and / or the surface to be cleaned. If the flow area is connected upstream of the valve device, then a measurement can be carried out even if the valve device is blocked.For example, before switching on a rotary drive, it is possible to determine whether the tank for cleaning fluid is sufficiently filled. If, for example, it is detected that there is no fluid in the flow area, the surface cleaning machine and thus the rotary drive can be prevented from switching on.

[0052] From a design perspective, it is advantageous if the flow area is located on the holder. In particular, the flow area is designed as a tube or hose attached to the holder.

[0053] In a structurally simple embodiment, the sensor device is designed as a resistance measuring device. In particular, it is then possible to check whether a first resistance state with high resistance or a second resistance state with a low resistance relative to the high resistance exists. The first resistance state indicates a flow area not filled with liquid. The second resistance state characterizes a flow area in which a liquid is present. This, in turn, can be used to determine the fill level of the tank device for cleaning liquid; at the very least, it can be stated that there is no more cleaning liquid in the tank device for cleaning liquid, or that cleaning liquid is still present.

[0054] In a structurally simple embodiment, the electrode device is supplied with a direct current or a direct voltage. A resistance determination can then be carried out, at least indirectly, via a reaction signal, which is in particular a voltage signal or current signal.

[0055] From a design perspective, it is advantageous if the sensor device comprises a first electrode and a second electrode spaced apart from the first electrode, the first electrode and the second electrode projecting into the flow area. The electrical resistance between the first electrode and the second electrode depends on whether there is liquid between the first and second electrodes. If there is cleaning liquid between the first and second electrodes, the resistance is low. If there is no liquid between the first and second electrodes, the resistance is high, which can ideally be regarded as infinite. By measuring the resistance, it is therefore possible to determine whether liquid is present or not.

[0056] In particular, the first electrode and the second electrode are located in a wall of the flow area and are, in particular, injected. This allows a fluid-tight flow area with an integrated sensor device to be easily formed.

[0057] It is advantageous from a design perspective if the first electrode and / or the second electrode are designed as metal pins.

[0058] It is particularly advantageous if the sensor device can determine whether the cleaning fluid tank is empty, whereby the absence of cleaning fluid in the flow area indicates that the cleaning fluid tank is empty. This allows the corresponding check to be carried out outside the cleaning fluid tank. This allows the cleaning fluid tank to be easily removable. The check can essentially be carried out regardless of the position. Sloshing of cleaning fluid in the tank has no significant impact on the check result.

[0059] It is advantageous if the sensor device is connected to an evaluation device in a signal-effective manner, wherein in particular at least one of the following is provided: the evaluation device determines a filling level of the tank device for cleaning fluid from sensor data of the sensor device; the evaluation device controls the sensor device; the evaluation device is connected to a display device and / or a transmitter for signaling purposes; the evaluation device initiates a warning signal if the tank device for cleaning fluid is detected as empty; the evaluation device switches off a rotation drive for the at least one cleaning roller unit if the tank device for cleaning fluid is detected as empty; the evaluation device prevents the switching on of a rotation drive for the at least one cleaning roller if the tank device for cleaning fluid is detected as empty when the surface cleaning machine is put into operation.

[0060] The evaluation device provides, for example, an actuation signal for the sensor device, such as a DC voltage signal. It then determines, in particular, a reaction signal, which can be used to determine whether liquid is present in the flow area.

[0061] The display device can indicate to the operator whether the tank is empty or not, and can also issue a warning signal, for example. The signal-effective connection of the evaluation device to a transmitter allows corresponding display signals or warning signals to be transmitted, for example, to a remote control or a mobile device such as a smartphone.

[0062] It is advantageous if the indicator is mounted on a handle, via which the cleaning head can be guided by an operator, and / or is mounted on the cleaning head itself. This allows the operator to easily determine the status of the cleaning fluid tank. For example, a visual and / or acoustic warning signal is emitted via the indicator.

[0063] The following description of preferred embodiments, in conjunction with the drawings, serves to further explain the invention. They show: Figure 1 shows a first embodiment of a surface cleaning machine according to the invention in a perspective view; Figure 2 shows a partial sectional view in the section plane E of the surface cleaning machine according to Figure 1 ; Figure 3 an enlarged view of area A according to Figure 2; Figure 4 is a perspective view of a second embodiment of a surface cleaning machine according to the invention; Figure 5 is an enlarged view of a cleaning head of the surface cleaning machine according to Figure 4 ; Figure 6 a sectional view of the cleaning head according to Figure 5 ; Figure 7 a bottom view of the cleaning head according to Figure 5 with the tank device for dirty fluid removed; Figure 8 shows a schematic sectional view of a third embodiment of a surface cleaning machine according to the invention; and Figure 9 shows a schematic representation of an evaluation device with a probe device for determining whether a tank device for cleaning fluid is empty, and with a sensor device for determining a filling level of a tank device for dirty fluid.

[0064] A first embodiment of a surface cleaning machine according to the invention, which is shown in Figure 1 is shown and in the Figures 2 ,3 shown in partial representation and designated 10, is designed in particular as a hand-held and hand-guided floor cleaning machine for hard floors.

[0065] The surface cleaning machine 10 comprises a device body 12 and a cleaning head 14. The cleaning head 14 is arranged on the device body 12.

[0066] During a cleaning process on a surface 16 to be cleaned, the surface cleaning machine 10 is supported on the surface 16 to be cleaned via a cleaning roller unit 18, and in particular a single cleaning roller unit 18. The cleaning roller unit 18 has a single axis of rotation (see below). The cleaning roller unit 18 is a cleaning roller that can be one-piece or multi-piece. In the embodiment described below, the cleaning roller unit 18 is a two-piece cleaning roller.

[0067] The device body 12 has a longitudinal axis 20. The surface cleaning machine 10 is supported or guided by a handle. For this purpose, a support rod device 22 is located on the device body 12.

[0068] In one embodiment, the holding rod device 22 comprises one (in particular, exactly one) holding rod 24, which has a longitudinal extension parallel to the longitudinal axis 20. A (hand)grip 26, in particular a bow handle, is arranged at an upper region of the holding rod device 22. An operator can hold the surface cleaning machine 10 with one hand using this handle 26 and guide it over the surface 16 to be cleaned (with the cleaning roller unit 18 supported thereon).

[0069] The holding rod device 22 can be designed to be variable in length or fixed in length with respect to a length in the longitudinal axis 20.

[0070] The surface cleaning machine 10 is dimensioned such that, with the cleaning roller unit 18 resting on the surface 16 to be cleaned, an operator can conveniently perform a cleaning operation on the surface 16 to be cleaned using an angled support arm. In particular, the length of the surface cleaning machine 10 along the longitudinal axis 20 between the cleaning roller unit 18 and the handle 26 is in a range between 60 cm and 130 cm.

[0071] In particular, one or more operating elements and display elements (see below) are arranged on the handle 26. For example, a switch is arranged, via which the surface cleaning machine 10 can be switched on or off for a cleaning operation. This switch can be used to switch the operation of a drive motor 28 for a rotational operation of the cleaning roller unit 18. Furthermore, a switch for actuating a valve device 38 (see below) can be provided.

[0072] The device body 12 comprises a housing 30 in which components of the surface cleaning machine 10 are arranged in a protected manner.

[0073] A holder 32 is arranged on the housing 30. A tank device 34 for cleaning fluid (in particular fresh water with or without an additional cleaning agent) is removably arranged on the holder 32.

[0074] In one embodiment, the tank device 34 comprises a single tank with, in particular, a single chamber for receiving cleaning fluid.

[0075] A valve device 38 is positioned in the housing 30.

[0076] One or more fluid lines 40 lead from the valve device 38 to the cleaning head 14.

[0077] The valve device 38 has a shut-off valve, via which the supply of cleaning fluid from the tank device 34 to the cleaning head 14 can be switchably shut off. A filter device 39 for cleaning fluid can be assigned to the valve device 38. The filter device 39 is, in particular, connected upstream of the shut-off valve and arranged between the valve device 38 and the tank receptacle 36.

[0078] When the shut-off valve is open, cleaning fluid can flow from the tank device 34 through the fluid line or fluid lines 40 to the cleaning head 14 and act on the surface 16 to be cleaned.

[0079] For this purpose, one or more outlet openings for cleaning fluid are provided on the cleaning head 14. It is generally possible for the outlet opening or outlet openings to be arranged such that the surface 16 to be cleaned is directly exposed to cleaning fluid.

[0080] In an advantageous variant, the outlet opening or outlet openings are arranged such that the cleaning roller unit 18, and in particular a filler 42 of the cleaning roller unit 18, is supplied with cleaning fluid. When the cleaning roller unit 18 is supplied with cleaning fluid, the surface 16 to be cleaned is then indirectly supplied with cleaning fluid.

[0081] The trim 42 is made in particular of a textile material.

[0082] The valve device 38 is assigned a switch by which the user can set whether the shut-off valve of the valve device 38 is blocked (i.e. the flow of cleaning fluid to the cleaning head 14 is blocked) or whether the shut-off valve is open (i.e. the flow of cleaning fluid from the tank device 34 to the cleaning head 14 is enabled).

[0083] This switch can be arranged on the housing 30. It is also possible, in principle, for the switch to be arranged on the handle 26.

[0084] In one embodiment, a battery device 44 for supplying electrical power to the drive motor 28 is arranged in the housing 30. The battery device 44 is rechargeable. This allows the surface cleaning machine 10 to be operated independently of a mains power supply.

[0085] However, it is also possible in principle for the surface cleaning machine 10 to be operated via mains power. In this case, a corresponding connection device for mains power is arranged on the surface cleaning machine 10.

[0086] The battery device 44 can be removable from the device body 12 in order to be able to recharge it using a corresponding charger.

[0087] It may also be provided that a corresponding charging device is integrated into the device body 12, allowing recharging without removing the battery device 44 from the device body 12. Corresponding connection sockets are arranged, for example, on the support rod 24.

[0088] The drive motor 28 is an electric motor. It has a motor axis 46. The motor axis 46 is coaxial with a rotational axis of the drive motor 28.

[0089] The drive motor 28 is located between the cleaning head 14 and the housing 30 on the device body 12.

[0090] In one embodiment, the motor axis 46 is oriented at an angle to the longitudinal axis 20 of the device body 12 (and the support rod 24). The angle between the motor axis 46 and the longitudinal axis 20 is, for example, in the range between 150° and 170°.

[0091] In one embodiment, the cleaning head 14 is pivotable about a pivot axis 48.

[0092] In particular, the pivot axis 48 is coaxial with the motor axis 46.

[0093] In one embodiment, the drive motor 28 is arranged on an inner sleeve 52. This inner sleeve 52 preferably forms an encapsulation of the drive motor 28.

[0094] An outer sleeve 54 is firmly attached to the device body 12. The inner sleeve 52 sits in the outer sleeve 54. The inner sleeve 52 can pivot about the pivot axis 48 relative to the outer sleeve 54, with the inner sleeve 52 being pivotally mounted in the outer sleeve 54. The inner sleeve 52 and the outer sleeve 54 form a pivot bearing 56 for the pivotability of the cleaning head 14 relative to the device body 12. The drive motor 28 can pivot about the pivot axis 48 relative to the device body 12. Corresponding supply lines from the battery device 44 to the drive motor 28 are arranged and designed to allow pivoting. Accordingly, the fluid line 40 or the fluid lines 40 are designed to allow this pivoting.

[0095] The pivot bearing 56 has a basic position which is defined, for example, by (the only) rotational axis 58 of the cleaning roller unit 18 being perpendicular to the plane E according to Figure 1 oriented.

[0096] A pivoting about the pivot axis 58 relative to this basic position results in an angular position of the rotation axis 58 relative to the plane E.

[0097] The pivot bearing 56 is in particular adjusted in such a way that, with respect to normal cleaning operation, a particular amount of force is required to cause the cleaning head 14 to pivot from its basic position.

[0098] The ability of the cleaning head 14 to pivot about the pivot axis 48 enables improved cleaning options even in places that are difficult to access, as the device body 12 with the holding rod device 22 can be "repositioned" relative to the surface 16 to be cleaned.

[0099] The cleaning head 14 has a cleaning roller holder 60, on which the cleaning roller unit 18 is mounted, rotatable about the rotation axis 58. The cleaning roller holder 60 is connected to the inner sleeve 52 in a rotationally fixed manner.

[0100] The cleaning roller holder 60 has a holding area 62 for the cleaning roller unit 18, and a receiving chamber 64 for a tank device 66 for dirty fluid.

[0101] The receiving chamber 64 is positioned between the holding area 62 and the inner sleeve 52. The inner sleeve 52 is, in particular, firmly connected to an outer side of the receiving chamber 64.

[0102] The cleaning roller unit 18 is torque-effectively coupled to the drive motor 28 via a gear device.

[0103] The gear device connects a motor shaft of the drive motor 28 (which rotates about the motor axis 46) with a shaft 70 for the cleaning roller unit 18 in a torque-effective manner.

[0104] In one embodiment, the transmission device includes a speed reducer. This serves to reduce the speed relative to the speed of the motor shaft. For example, a standard electric motor has speeds in the order of 7,000 revolutions per minute. The speed reducer ensures a reduction in the speed to, for example, approximately 400 revolutions per minute.

[0105] The speed reducer can be arranged in the inner sleeve 52 or outside the inner sleeve 52 on the cleaning roller holder 60.

[0106] The speed reducer is designed as a planetary gear, for example.

[0107] The transmission device further comprises an angular gear, which provides torque deflection to drive the cleaning roller unit 18 with the rotational axis 58 transverse (and in particular perpendicular) to the motor axis 46. The angular gear is connected downstream of the speed reducer.

[0108] In one embodiment, the bevel gear comprises one or more gears that are non-rotatably coupled to a corresponding shaft of the speed reducer. These gears act on a bevel gear for angle conversion.

[0109] In one embodiment, the transmission device further comprises a belt that is torque-effectively coupled to the bevel gear and acts on the shaft 70. The belt bridges the distance between the shaft 70 and the bevel gear and provides a speed reduction.

[0110] In one embodiment, the cleaning roller unit 18 is formed in two parts with a first part 72 and a second part 74. The first part 72 is seated in a rotationally fixed manner on a first side of the shaft 70 and the second part 74 is seated in a rotationally fixed manner on a second side opposite the first side of the shaft 70.

[0111] The gear mechanism is guided in an intermediate region 76 between the first part 72 and the second part 74 and is coupled to the shaft 70. They have the same rotation axis 58.

[0112] The cleaning roller unit 18, or rather the first part 72 and the second part 74 of the cleaning roller unit 18, has a sleeve 78 which is cylindrical in shape. The trim 42 is arranged on the sleeve 78. The cleaning roller unit 18, or rather the first part 72 and the second part 74, is fixed to the shaft 70 via the sleeve 78.

[0113] The cleaning roller unit 18 is arranged on the cleaning head 14 such that the rotation axis 58 is oriented perpendicular to the longitudinal axis 20.

[0114] The cleaning roller unit 18 has a length along the rotation axis 58 between a first end face 80 (which is formed on the first part 72) and a second end face 82 (which is formed on the second part 74), which is considerably greater than a corresponding width of the device body 12 perpendicular to the longitudinal axis 20. In particular, a length of the cleaning roller unit 18 between the first end face 80 and the second end face 82 is at least 20 cm and preferably at least 25 cm.

[0115] The receiving chamber 64 has a bottom. A receiving chamber wall is arranged on the bottom, oriented transversely thereto. The receiving chamber wall and the bottom of the receiving chamber 64 define a receiving space for the tank device 66 for dirty fluid.

[0116] Opposite the floor, the receiving space is open. The dirty fluid tank device 66 can be removed from or inserted into the receiving space via a corresponding side. A removal direction or insertion direction 92 is essentially perpendicular to the floor (and perpendicular to the rotation axis 58).

[0117] A fixing device is assigned to the receiving chamber 64, via which the tank device 66 for dirty fluid can be fixed in a holding position on the receiving chamber wall. Fixing is achieved, in particular, by means of a positive locking mechanism.

[0118] In one embodiment, the fixing device 98 comprises a flap 102, which is arranged on the cleaning head 14 so as to be pivotable about a pivot axis by means of a pivot bearing 106. The pivot bearing 106 is positioned on or near the inner sleeve 52.

[0119] The pivot axis is oriented parallel to the rotation axis 58 of the rotating roller 18.

[0120] In the holding position, the flap 102 acts on the tank device 66 for dirty fluid and holds it at the receiving chamber 64 in the receiving space.

[0121] In order to remove the tank device 66 from the cleaning head 14, the flap 102 can be pivoted from this holding position in the direction of the device body 12 in order to release the tank device 66 so that it can be removed from the receiving space on the side in the removal direction and can be removed from the cleaning head 14.

[0122] Regarding the further design of the surface cleaning machine 10, reference is made to WO 2017 / 153450 A1.

[0123] The cleaning head 14 has a stripping guide device 110, which acts on the cleaning roller unit 18 (and thereby on the first part 72 and the second part 74) and serves to release dirty fluid (in particular water with dirt particles) carried along by the cleaning roller unit 18 and to feed it to an inlet opening 112 of the dirty fluid tank device 66. This then couples dirty fluid into the dirty fluid tank device 66.

[0124] The scraper guide device 110 is designed such that it scrapes dirt fluid from the cleaning roller unit 18 and guides it into the inlet opening 112.

[0125] It is possible that, when the cleaning roller unit 18 rotates, a guiding effect is achieved via the action of the centrifugal force and, to a certain extent, dirty fluid is thrown into the dirty fluid tank device 66.

[0126] The stripping guide device 110 is spaced from the rotation axis 58.

[0127] In one embodiment (see for example Figure 5 ), the stripping guide device 110 projects with a depth T into the facing 42 of the cleaning roller unit 18. The depth T is in particular at least 5% of a thickness D of the facing 42 of the cleaning roller unit 18 based on a moist state of the facing 42.

[0128] The stripping guide device 110 is formed in particular by one or more edge elements. For example, a respective edge element is assigned to the first part 72 and the second part 74 of the cleaning roller unit 18.

[0129] Regarding the further design of the surface cleaning machine 10, reference is made to WO 2017 / 153450 A1.

[0130] The holder 32 for the tank device 34 for cleaning fluid has a transverse area 114 (compare Figure 3), which projects transversely from the support rod 24 relative to the longitudinal axis 20. The tank device 34 can be placed onto this transverse region 114 and fixed to the transverse region 114, wherein additional fixation to the support rod 24 can be provided. In one embodiment, the tank device 34 is designed such that the tank device 34 can be clamped between the transverse region 114 and a spaced-apart support web 116.

[0131] The tank device 34 for cleaning fluid has an outlet 118.

[0132] A connection 120 for the tank device 34 is arranged on the transverse region 114. This connection 120 can be fluidly connected to the outlet 118, so that cleaning fluid can be coupled into the device via the connection 120. The connection 120 is fluidly connected to the fluid line 40 via a flow area 122, or the flow area 122 can be considered part of the fluid line 40.

[0133] The flow area 122 is arranged downstream of the tank device 34 for cleaning fluid and is also arranged downstream of the connection 120 with respect to a flow direction 124 for cleaning fluid flowing from the tank device 34 into the line 40.

[0134] The flow area 122 is formed, in particular, by a tube area that is integrated into the holder 32 and, in this case, into the transverse area 114 of the holder 32 or arranged thereon. In particular, the flow area 122 is in direct fluid communication with the connection 120. The connection 120 forms an inlet of the flow area 122.

[0135] The pipe area is designed in particular as a rigid pipe area.

[0136] A sensor device 126 is arranged at the flow area, which checks whether liquid (cleaning liquid) is present in the flow area 122. If no cleaning liquid is present in the flow area 122, this means that the tank device 34 for cleaning liquid is empty. The presence of cleaning liquid in the flow area 122 can be used to determine the filling state of the tank device 34 for cleaning liquid with cleaning liquid, i.e., in particular, it can be detected whether the tank device 34 is empty.

[0137] In particular, it is provided that the flow area 122 is arranged upstream of the valve device 38 with respect to the flow direction 124 for cleaning fluid.

[0138] In particular, it is provided that during operation of the surface cleaning machine 10, cleaning fluid is supplied to the cleaning roller unit 18 by gravity. In particular, there is no pump present to convey the cleaning fluid.

[0139] In one embodiment, the flow area 122 is arranged downstream of the filter device 39. However, it can also be arranged upstream of the filter device 39.

[0140] The sensor device 126 is designed, in particular, as a resistance measuring device. It is designed as an electrode device. For this purpose, it comprises a first electrode 128 and a second electrode 130. The first electrode 128 and the second electrode 130 are spaced apart from one another. They extend into the flow area 122, being immersed in the cleaning fluid (if cleaning fluid is present in the flow area 122).

[0141] In one embodiment, the flow region 122 comprises a wall 132, wherein the first electrode 128 and the second electrode 130 are arranged on the wall 132 and in particular are arranged in the wall 132.

[0142] In one embodiment, the first electrode 128 and the second electrode 130 are formed as metal pins. In particular, the first electrode 128 and the second electrode 130 are injected or pressed into the wall. This results in a fluid-tight seal of the flow region 122 at the first electrode 128 and the second electrode 130.

[0143] The first electrode 128 and the second electrode 130 are connected to an evaluation device 134. For example, a connection is provided via respective lines 136a, 136b.

[0144] The evaluation device 134 functions with the sensor device 126 basically as follows:

[0145] A voltage, in particular a direct voltage, is applied between the first electrode 128 and the second electrode 130. The direct voltage can be applied continuously or pulsed.

[0146] When liquid (cleaning liquid) is present in the flow region 122, the electrical resistance between the first electrode 128 and the second electrode 130 is relatively low. When no liquid is present in the flow region 122, an air bridge exists between the first electrode 128 and the second electrode 130 within the flow region 122.

[0147] Preferably, the wall 132 is made of a plastic material that is an electrical insulator. Therefore, if there is no liquid in the flow area 122, and thus also no liquid between the first electrode 128 and the second electrode 130, then a high resistance is present. Thus, by measuring the resistance, it is possible to determine whether or not there is liquid in the flow area 122. If it is detected that there is no liquid in the flow area 122, this means that the tank device 34 for cleaning fluid is emptied or empty.

[0148] In particular, it is provided that, with regard to proper operation of the surface cleaning machine 10, in which the latter is positioned on the surface 16 to be cleaned via the cleaning roller unit 18, the flow area 122 is located below the tank device 34 for cleaning fluid and thus below the outlet 118 with respect to the direction of gravity g.

[0149] If the valve device 38 is located downstream of the flow area 122, this means that for proper operation, the flow area 122 is filled with fluid when the tank device 34 is inserted and contains sufficient fluid. This makes it possible, for example, to check whether sufficient cleaning fluid is available for cleaning operation even before the rotary drive is switched on (via the drive motor 28).

[0150] The evaluation device 134 also serves to control the sensor device 126 with the electrodes 128, 130. For example, the evaluation device 134 comprises an ASIC 138 ( Figure 9 ).

[0151] For measuring operation of the sensor device 126, for example, a direct voltage (which may also be pulsed) is applied between the first electrode 128 and the second electrode 130. A decreasing voltage is measured as a response signal.

[0152] When there is fluid in the flow area 122, there is a resistance between the first electrode 128 and the second electrode 130 due to this medium. If there is no fluid between the first electrode 128 and the second electrode 130, this resistance can be ideally considered infinite.

[0153] If liquid is present between the electrodes 128, 130, a current can flow. This results in a finite resistance. By simply testing the threshold value of the resistance, the presence of liquid in the flow region 122 can then be determined via the evaluation device 134.

[0154] The sensor device 126 is connected to the evaluation device 134 for signal transmission. The evaluation device 134 is connected to a display device 140 for signal transmission. The display device 140 comprises a visual and / or acoustic display. In one embodiment, the display device 140 comprises a visual display 142, which is arranged on the handle 26.

[0155] The optical display 142 indicates, for example by flashing or the like, that the tank device 34 for cleaning fluid is empty.

[0156] Alternatively or additionally, the evaluation device 134 is connected to a transmitter 144 for signaling purposes. The transmitter 144 can transmit corresponding signals, in particular warning signals or display signals, to a remote control 146 or a mobile device such as a smartphone. This can then provide a corresponding warning display or indicate whether the filling level of the tank device 34 for cleaning fluid is sufficient or not.

[0157] The sensor device 126 makes it easy to detect an empty state of the cleaning fluid tank device 34, and the corresponding state can be easily communicated to an operator via the display device 140. This determination is essentially position-independent due to the arrangement of the flow area 122 below the connection 120.

[0158] The flow area 122 is arranged on the transverse area 114 of the holder 32 and, in particular, is firmly connected thereto. This allows the system with the sensor device 126 to be designed in a structurally simple manner. No part of the sensor device 126 needs to be movable, i.e., a reduction in the tank device 34 for cleaning fluid does not need to be considered in the design of the sensor device 126. Sloshing of fluid in the tank device 34 for cleaning fluid and a position-dependent fluid level in the tank device 34 for cleaning fluid do not affect the sensor device 126.

[0159] The sensor device 126 is arranged outside the tank device 34 for cleaning fluid. A current between the first electrode 128 and the second electrode 130 breaks down when the tank device 34 for cleaning fluid is empty and, as a result, there is no longer any fluid in the flow area 122.

[0160] The following is possible via the evaluation device 134: If it is detected before commissioning of the rotary drive that the tank device 34 for cleaning fluid is empty, then a rotary drive of the cleaning roller unit 18 can be prevented via the evaluation device 134.

[0161] If, during operation of the surface cleaning machine 10 (with rotating cleaning roller unit 18), it is detected that the tank device 34 for cleaning fluid has been emptied, the evaluation device 134 can initiate a corresponding display signal and, in particular, a warning signal via the display device 140 or via the transmitter 144.

[0162] If emptying of the tank device 34 for cleaning fluid is detected during operation, the evaluation device 134 can shut off the rotation of the cleaning roller unit 18 by appropriately controlling the drive motor 28. This prevents, for example, damage to a surface 16 to be cleaned.

[0163] The surface cleaning machine 10 functions as follows: In a cleaning operation, the dirty fluid tank device 66 is fixed to the cleaning head 14 in the holding position.

[0164] For a cleaning operation, the surface cleaning machine 10 is placed on the surface 16 to be cleaned using only the cleaning roller unit 18. The drive motor 28 drives the cleaning roller unit 18 in a rotational movement about the (single) rotation axis 58 in the rotation direction 158.

[0165] The cleaning roller unit 18 is supplied with cleaning fluid from the tank device 34.

[0166] Dirt on the surface 16 to be cleaned is moistened when the moistened coating 42 of the cleaning roller unit 18 acts on it, in order to make it easier to remove.

[0167] The rotation of the cleaning roller unit 18 causes a mechanical action on dirt on the surface 16 to be cleaned in order to achieve better detachability from the surface 16 to be cleaned.

[0168] Any coarse dirt can be fed into the cleaning roller unit 18 using a sweeping element.

[0169] Dirty fluid (dirt particles, cleaning fluid with dissolved dirt) is entrained by the cleaning roller unit 18. At the stripping guide device 110, the dirty fluid is released from the cleaning roller unit 18 and guided (among other things under the influence of centrifugal force) into the inlet opening 112, from where it reaches the dirty fluid tank device 66. The stripping guide device 110 ensures that the dirty fluid is released from the filling 42 of the cleaning roller unit 18 by stripping.

[0170] The coupling of dirty fluid into the tank device 66 for dirty fluid takes place in particular without a suction fan.

[0171] In an alternative embodiment, it is provided that dirty fluid is sucked away from the cleaning roller unit 18 via a corresponding suction device.

[0172] The evaluation device 134 with the sensor device 126 determines whether the tank device 34 for cleaning fluid is empty. The appropriate measures can then be taken via the evaluation device 134.

[0173] A second embodiment of a surface cleaning machine 210 ( Figures 4 to 7 ) comprises a cleaning head 212. The cleaning head 212 has a head body 214. A first cleaning roller unit 216 and a second roller unit in the form of a second cleaning roller unit 218 are arranged on the head body 214 and are spaced apart from one another.

[0174] In one embodiment, the first cleaning roller unit 216 and the second cleaning roller unit 218 are formed as one piece, i.e., the respective cleaning roller unit is formed by a one-piece cleaning roller.

[0175] It is also possible in principle for the first cleaning roller unit 216 and / or the second cleaning roller unit 218 to be formed in several parts and in particular to be formed in two parts each.

[0176] The first cleaning roller unit 216 and the second cleaning roller unit 218 each comprise a (cylindrical) carrier 220, on which a facing 222 made of a textile material is arranged. Via the facing 222, the surface cleaning machine acts with its cleaning head 212 on a surface 224 to be cleaned.

[0177] The first cleaning roller unit 216 is driven to rotate about a first rotation axis 226 (during operation of the surface cleaning machine 210).

[0178] During operation, the second cleaning roller unit 218 is driven to rotate about a second rotation axis 228. The first rotation axis 226 and the second rotation axis 228 are spaced parallel to each other.

[0179] When the cleaning head 212 with the first cleaning roller unit 216 and the second cleaning roller unit 218 is placed on a flat surface 224 to be cleaned, being supported on the surface 224 to be cleaned via the first cleaning roller unit 216 and the second cleaning roller unit 218, the first rotation axis 226 and the second rotation axis 228 are each parallel to the surface 224 to be cleaned.

[0180] The surface cleaning machine 210 comprises a drive device 230 for the respective rotational drive of the first cleaning roller unit 216 and the second cleaning roller unit 218.

[0181] In one embodiment, the drive device 230 comprises a first drive 232, which drives the rotational movement of the first cleaning roller unit 216, and a second drive 234, which drives the rotational movement of the second cleaning roller unit 218.

[0182] The first drive 232 and the second drive 234 are formed in particular by electric motors.

[0183] The first drive 232 and the second drive 234 are positioned in particular within the respective carrier 220 of the first cleaning roller unit 216 and the second cleaning roller unit 218, respectively.

[0184] It is then provided in particular that the first cleaning roller unit 216 and the second cleaning roller unit 218 are each formed in one piece.

[0185] It is provided that the first cleaning roller unit 216 is driven to rotate in a first rotational direction 236, and the second cleaning roller unit 218 is driven to rotate in a second rotational direction 238. The first rotational direction 236 and the second rotational direction 238 are opposite to each other, i.e., the first cleaning roller unit 216 and the second cleaning roller unit 218 are driven in opposite directions.

[0186] The first direction of rotation 236 is such that a first region 240, with which the first cleaning roller unit 216 has acted on the surface 224 to be cleaned, is first moved towards a region 242 which lies between the first cleaning roller unit 216 and the second cleaning roller unit 218 on the head body 214.

[0187] Accordingly, the second direction of rotation 238 is such that a second region 244, with which the second cleaning roller unit 218 has acted on the surface 224 to be cleaned, is moved towards the region 242 on the head body 214.

[0188] In one embodiment, the surface cleaning machine 210 comprises an adjustment device (in Figure 6indicated by the reference numeral 246), by means of which a rotational speed of the first cleaning roller unit 216 in the first rotational direction 236 and / or a rotational speed of the second cleaning roller unit 218 in the second rotational direction 238 can be adjusted by an operator.

[0189] If the rotational speed of the first cleaning roller unit 216 and the second cleaning roller unit 218 is the same, then the cleaning head 212 does not experience any feed movement due to rotation of the cleaning roller unit 216 and 218.

[0190] If the rotational speed of the first cleaning roller unit 216 is greater than the rotational speed of the second cleaning roller unit 218, the cleaning head 212 experiences a feed movement in a first feed direction 248. If the rotational speed of the second cleaning roller unit 218 is greater than the rotational speed of the first cleaning roller unit 216, the cleaning head 212 experiences a feed movement in a second feed direction 250.

[0191] The first feed direction 248 and the second feed direction 250 are opposite to each other.

[0192] The first feed direction 248 and the second feed direction 250 are transverse and in particular at right angles to the rotation axes 226 and 228.

[0193] By means of a corresponding setting on the setting device 246, it is possible to control whether there is no feed movement or a feed movement in the first feed direction 248 or the second feed direction 250.

[0194] A support rod assembly 254 is attached to the cleaning head 212 via a joint 252. The support rod assembly 254 can be pivoted about a pivot axis 256 toward the cleaning head 212 via the joint 252 when the cleaning head 212, with its first cleaning roller unit 216 and the second cleaning roller unit 218, rests on the surface 224 to be cleaned.

[0195] The pivot axis 256 is parallel to the first rotation axis 226 and the second rotation axis 228.

[0196] In the region of a proximal end 258, a (hand)grip and in particular a bow handle 260 is located on the holding rod device 254. In the region of a distal end 262, the holding rod device is articulated to the cleaning head 212 via the joint 252.

[0197] An operator standing on the surface 224 to be cleaned behind the cleaning head 212 can grasp the handle 260 with one hand. Due to the pivotability of the holding rod device 254 at the joint 252, a pivot angle of the holding rod device 254 relative to the surface 224 to be cleaned is adjustable, and an operator can, in particular, adjust this pivot angle according to his or her body size.

[0198] The surface cleaning machine 210 is hand-held and hand-guided by the handle 260.

[0199] A battery device 264, which is particularly rechargeable, is arranged on the support rod device 254. The drive device 230 is supplied with electrical energy via the battery device 264.

[0200] It is also possible in principle for a mains connection to be arranged on the holding rod device, in which case the drive device 230 can be supplied with electrical energy via mains current.

[0201] Furthermore, a tank device 266 for cleaning fluid is arranged on the holding rod device 254.

[0202] From the tank device 266, at least one channel leads through the holding rod device 254 to the cleaning head 212 and through the latter to a first outlet opening device 268, which is assigned to the first cleaning roller unit 216, and a second outlet opening device 270, which is assigned to the second cleaning roller unit 218.

[0203] In one embodiment, the tank device 266 is associated with a sensor device corresponding to the sensor device 126 as described above.

[0204] The first outlet opening device 268 is arranged above the first cleaning roller unit 216 with respect to a height direction away from the surface 224 to be cleaned when the cleaning head 212 is properly positioned thereon, and the second outlet opening device 270 is arranged above the second cleaning roller unit 218.

[0205] In one embodiment, the tank device 266 for cleaning fluid is assigned a valve device which is designed such that when the drive device 230 is operated, it opens automatically and cleaning fluid thereby flows from the tank device 266 via the first outlet opening device 268 onto the first cleaning roller unit 216 and via the second outlet opening device 270 onto the second cleaning roller unit 218.

[0206] The first outlet opening device 268 and the second outlet opening device 270 are designed in particular such that the first cleaning roller unit 216 and the second cleaning roller unit 218 are respectively supplied with cleaning fluid over a large length range parallel to the respective rotational axis 226, 228.

[0207] A region of the first cleaning roller unit 216, which has been supplied with cleaning fluid via the first outlet opening device 268, rotates in the first rotation direction 236 toward the surface 224 to be cleaned and then forms the first region 240 upon contact with this surface 224 to be cleaned. The first cleaning roller unit 216 acts mechanically on the surface 224 to be cleaned. The "fluid content" causes dirt to dissolve and thus improves the cleaning effect.

[0208] Accordingly, a moistened region of the second cleaning roller unit 218 rotates in the second rotation direction 238 toward the surface 224 to be cleaned and forms the second region 244 with the same functionality as described with reference to the first cleaning roller unit 216.

[0209] After impacting the surface 224 to be cleaned, the first cleaning roller unit 216 carries dirt in the first rotational direction 236. The second cleaning roller unit 218 carries dirt in the second rotational direction 238.

[0210] In principle, it is also possible for the tank device 266 to be arranged on the cleaning head 212.

[0211] A first sweeping element 272 is located on the cleaning head 212 and is assigned to the first cleaning roller unit 216. Furthermore, a second sweeping element 274 is located on the cleaning head 212 and is assigned to the second cleaning roller unit 218.

[0212] The first sweeping element 272 and the second sweeping element 274 project downwards beyond the head body 214 onto the surface 224 to be cleaned.

[0213] The task of the first sweeping element 272 is to hold coarse dirt in position, i.e., to prevent it from reaching a region from the first cleaning roller unit 216 to the second cleaning roller unit 218. Coarse dirt can be collected on the first sweeping element 272, which can then be carried along by the rotation of the first cleaning roller unit 216 in the first rotation direction 236.

[0214] The second sweeping element 274 has the same function with respect to the second cleaning roller unit 218.

[0215] In principle, it is also possible that only the first sweeping element 272 or the second sweeping element 274 is present.

[0216] In one embodiment, the surface cleaning machine 210 comprises a blower device 278. The blower device comprises a blower and a drive motor, in particular an electric motor. This electric motor is supplied with electrical energy via the battery device 264 or, alternatively, via mains power. The blower device 278 generates a negative pressure to form a suction flow.

[0217] From the blower device 278, channels 280, 282 lead to a first inlet opening device 284 ( Figure 4 ), which is assigned to the first cleaning roller unit 216 or to a second inlet opening device 286, which is assigned to the second cleaning roller unit 218.

[0218] The corresponding suction flow allows dirty fluid to be sucked away from the first cleaning roller unit 216 and discharged via the first inlet opening device 284. Furthermore, dirty fluid can be sucked away from the second cleaning roller unit 218 and discharged via the second inlet opening device 286.

[0219] The blower device 278 is assigned a tank device 288 for dirty fluid, into which dirty fluid is coupled.

[0220] The tank device 288 can be arranged on the holding rod device 254 in particular in a detachable manner.

[0221] In one embodiment, the tank device 288 is arranged on the cleaning head 212, in particular between the first cleaning roller unit 216 and the second cleaning roller unit 218. Such a tank device is shown in Figure 6 indicated by the reference number 290.

[0222] The dirty fluid tank device 288 or 290 is correspondingly fluidically connected to the blower device 278 so that dirty fluid can be coupled into it.

[0223] In one embodiment, the first inlet opening device 284 is arranged upstream of the first outlet opening device 268 with respect to the first rotation direction 236, i.e., the first region 240, which has acted on the surface 224 to be cleaned, is first guided past the first inlet opening device 284 before being guided past the first outlet opening device 268. The same applies to the second cleaning roller unit 218 with its second region 244 in conjunction with the second inlet opening device 286.

[0224] With respect to the first rotation direction 236, the first inlet opening device 284 is arranged between the first sweeping element 272 and the first outlet opening device 268.

[0225] With respect to the direction of rotation 238, the second inlet opening device 286 is arranged between the second sweeping element 274 and the second outlet opening device 270.

[0226] In Figure 5 The position of the first inlet opening device 284 and the second inlet opening device 286 is indicated accordingly. The first inlet opening device 284 points into a first receptacle 292 of the cleaning head 212, in which the first cleaning roller unit 216 is arranged. Relative to a height direction away from the surface 224 to be cleaned, when the cleaning head 212 with the first cleaning roller unit 216 and the second cleaning roller unit 218 is properly positioned on the surface to be cleaned, the first inlet opening device 284 is located above the first cleaning roller unit 216.

[0227] The second inlet opening device 286 is arranged accordingly in relation to the second cleaning roller unit 218. The second cleaning roller unit 218 sits in a second receptacle 294 of the cleaning head 212, and the second inlet opening device 286 points into this second receptacle 294.

[0228] This allows dirty fluid to be directly sucked off from the first cleaning roller unit 216 or second cleaning roller unit 218.

[0229] The first inlet opening device 284 and the second inlet opening device 286 have such an opening length parallel to the first rotational axis 226 and the second rotational axis 228, respectively, that a correspondingly large length range of the first cleaning roller unit 216 and the second cleaning roller unit 218, respectively, can be vacuumed.

[0230] For example, it is also possible that only inlet opening devices corresponding to the inlet opening devices 296 and 298, which are arranged next to the corresponding cleaning roller unit 216 and 218, are fluidly connected to the blower device 278. For example, it is possible that a first inlet opening device 300 is assigned to the first cleaning roller unit, and a second inlet opening device 302 is assigned to the second cleaning roller unit 218, which open directly into the tank device 290 ( Figure 6). In particular, a respective scraper 304 and 306 is then assigned to the first inlet opening device 200 and the second inlet opening device 202, which scrapes dirty fluid from the first cleaning roller unit 216 and the second cleaning roller unit 218, respectively. Dirt fluid can then be coupled directly into the tank device 290 via the first inlet opening device 296 and the second inlet opening device 298, respectively. In this case, in particular, the first inlet opening device 300 and the second inlet opening device 302 are not connected to the blower device 278. For example, suction then takes place at the inlet opening devices 296, 298, and direct scraping coupling takes place at the inlet opening devices 300 and 302.

[0231] For operation of the surface cleaning machine 210, the cleaning head 212 is placed on the surface to be cleaned via the first cleaning roller unit 216 and the second cleaning roller unit 218. These are driven to rotate in the first rotation direction 236 and the second rotation direction 238, respectively. By varying the rotational speed, a feed in the direction 248 and 250 can be adjusted.

[0232] The respective cleaning roller unit 216 or 218 is supplied with cleaning fluid from the tank device at the first outlet opening device 268 or the second outlet opening device 270, respectively. The respective rotating cleaning roller unit 216 or 218 acts mechanically on the surface to be cleaned via the first region 240 of the first cleaning roller unit 216 or the second region 244 of the second cleaning roller unit 218, and dirt is removed. Moistening via cleaning fluid at the tank device supports the removal of dirt.

[0233] Dirt is picked up by the trim 222 of the first and second cleaning roller units 216 and 218, respectively, and conveyed in the first rotational direction 236 and second rotational direction 238, respectively.

[0234] Any coarse dirt that may accumulate on the first sweeping element 272 or on the second sweeping element 274 is carried along in the first direction of rotation 236 or the second direction of rotation 238.

[0235] Depending on the design of the cleaning head 212, dirty fluid is sucked off, for example, at the first inlet opening device 284 and the second inlet opening device 286 via the blower device 278.

[0236] It is also possible for coupling into the tank device 290 for dirty fluid to take place at a corresponding first inlet opening device 300 and a second inlet opening device 302 without the need for a blower by stripping (cf. Figure 6 ).

[0237] The surface cleaning machine 210 is provided with two counter-rotating cleaning roller units 216, 218. This allows full contact pressure to be applied to the surface 224 to be cleaned, regardless of the pivoting position of the holding rod device 254 relative to the surface 224 to be cleaned.

[0238] Furthermore, a constant distance between the sweeping elements 272, 274 and the surface 224 to be cleaned can be ensured.

[0239] Furthermore, dirt thrown through one cleaning roller unit 216 or 218 can be captured by the other cleaning roller unit 218 or 216.

[0240] The tank device 290 for dirty fluid is positioned between the first cleaning roller unit 216 and the second cleaning roller unit 218. This results in a short transport path for dirty fluid, at least for direct coupling. Furthermore, the center of gravity can be kept low, resulting in less cleaning effort for the tank device.

[0241] The tank device 290 for dirty fluid is assigned a probe device 310 ( Figures 4 to 7 , Figure 9 ), by means of which a filling level of dirty fluid in the tank device 290 can be determined.

[0242] The probe device 310 is designed in particular as an electrode device or resistance measuring device. The probe device 310 comprises a first electrode 312 and a second electrode 314 arranged at a distance from the first electrode.

[0243] The first electrode 312 and the second electrode 314 are arranged and designed such that they protrude into a receiving space 316 of the tank device 290 for dirty fluid.

[0244] They are positioned at a distance from a tank bottom 318 of the tank device 290 for dirty fluid. They are arranged so that when the liquid level 320 rises (compare Figure 6 ) in the receiving space 316, this liquid level 320 rises in the direction of the electrodes 312, 314.

[0245] A direct current voltage is applied between the first electrode 312 and the second electrode 314. This voltage can also be pulsed.

[0246] If the liquid level 320 is below the electrodes 312, 314 (compare Figure 9), then an air bridge exists between the electrodes 312, 314, and no current can flow. Ideally, this can be viewed as meaning that the electrical resistance between the first electrode 312 and the second electrode 314 is infinite.

[0247] When the liquid level 320 reaches the electrodes 312, 314, a current can flow through the liquid between the first electrode 312 and the second electrode 314. This results in a finite resistance. The transition from the idealized infinite resistance to the finite resistance is measurable. This allows one to determine whether the liquid level 320 reaches a certain filling level 322. The specific filling level is predetermined by the arrangement of the first electrode 312 and the second electrode 314.

[0248] In particular, the probe device 310 is connected to an evaluation device. In one embodiment, this evaluation device corresponds to the evaluation device 134 for the sensor device 126. A separate evaluation device may also be provided for the probe device 310.

[0249] For example, a voltage is applied between the first electrode 312 and the second electrode 314 via a terminal 324 of an ASIC, which is in particular the ASIC 138. The corresponding voltage forms an application signal. A falling voltage, which is present in particular at a terminal 326, is the corresponding response signal.

[0250] A resistance exists between the first electrode 312 and the second electrode 314. If there is no liquid between the electrodes, this resistance can be ideally considered infinite. When the liquid level 320 reaches the electrodes 312, 314, a current can flow. This causes the resistance to become finite, and the voltage present at terminal 326 changes. This change is caused by the liquid level 320 reaching the specific fill level 322. This threshold value 322 can thus be detected accordingly, and the liquid level 320 can be determined, at least digitally.

[0251] A display device 328 is provided, which can visually and / or acoustically indicate to an operator that the specific filling level 322 of the tank device 290 for dirty fluid has been reached. The display device 328 comprises an optical and / or acoustic element 330, which is arranged in particular on the handle 60. For example, the optical element 330 flashes when the specific filling level 322 is reached.

[0252] Alternatively or additionally, the evaluation device 134 is connected to a transmitter corresponding to the transmitter 144 in order to be able to supply a remote control or a mobile device 146 with corresponding warning signals or display signals.

[0253] The evaluation device 134 enables, in particular, the following: The evaluation device 134 supplies the probe device 310 with a direct voltage, which can also be pulsed. A voltage is produced as a response signal, which is present in particular at the terminal 326. A resistance measurement can be performed, at least indirectly. This allows checking whether the specified filling level 322 has been reached.

[0254] In principle, during operation of the surface cleaning machine 210, sloshing of liquid may occur in the receiving space 316 of the tank device 290. It is provided that the evaluation device 134 has a filter device that can detect short-term resistance changes. With regard to determining the fill level 322, only longer-lasting conditions are used. This allows for a reliable determination of whether the specific fill level 322 has been reached; this allows, in a sense, to filter out short-term sloshing processes.

[0255] If it is detected that the specific filling level 322 has been reached (in the long term), the evaluation device 134 ensures that a corresponding signal is applied to the display device 328 or the transmitter 144. In particular, corresponding warning signals are initiated or emitted.

[0256] It can also be provided that, when it is detected that the specific filling level 322 has been reached, a rotary drive of the cleaning roller units 16, 18 is switched off and / or the operation of a blower device is switched off in order to prevent further coupling of dirty fluid into the tank device 290.

[0257] It can also be provided that, for example, if it is detected before the surface cleaning machine 210 starts operating that the specific filling level 322 has been reached, a rotary drive of the cleaning roller units 216, 218 is blocked or the operation of a blower device is blocked.

[0258] In principle, it is possible for the probe device 310 to also be used, for example, in the surface cleaning machine 10, in which the sensor device 126 is assigned to the corresponding tank device 34 for cleaning fluid.

[0259] Furthermore, it is possible that a probe device corresponding to the probe device 310 is used for the tank device 66 for dirty fluid of the surface cleaning machine 10.

[0260] In the surface cleaning machine 210, the tank device 290 for dirty fluid is positioned between the first cleaning roller unit 216 and the second cleaning roller unit 218. A cover wall 332 is provided (see Figure 7 ), which covers the tank device 290 upwards (in Figure 7 this tank facility is 290 away).

[0261] The first electrode 312 and the second electrode 314 are located on the cover wall 332. They are oriented transversely to a plane 334 ( Figure 7 ), this plane 334 containing the first rotation axis 226 and the second rotation axis 228.

[0262] In one embodiment, the cover wall 332 forms a cover for the dirty fluid tank assembly 290.

[0263] In principle, it is possible for the probe device 310 to comprise a plurality of electrode pairs. This also allows different intermediate stages to be detected until the specific filling level 322 is reached.

[0264] As mentioned above, the probe device 310 can also be used, for example, in the tank device 66 of the surface cleaning machine 10.

[0265] A third embodiment of a surface cleaning machine according to the invention, which is shown in Figure 8 shown schematically and designated 340, is a self-propelled and self-steering device ("cleaning robot").

[0266] The surface cleaning machine 340 comprises a cleaning head 342. A first cleaning roller unit 344 is arranged on the cleaning head 342. This unit is rotatable about a first rotation axis 346. For this purpose, a corresponding rotation drive is arranged on the cleaning head 342 (in Figure 8 not shown).

[0267] A second roller unit 348 is arranged on the cleaning head 342 at a distance from the first cleaning roller unit 344. The second roller unit is rotatable about a second rotation axis 350. In particular, it is rotationally driven via a corresponding rotation drive.

[0268] The cleaning head 342 and thus the surface cleaning machine 340 is supported on the surface 16 to be cleaned via the first cleaning roller unit 344 and the second cleaning roller unit 348.

[0269] The second roller unit 348 is designed, for example, as a sweeping roller unit.

[0270] A moistening device 352 is provided, via which cleaning fluid (fresh water with or without a cleaning agent) can be supplied to (at least) the first cleaning roller unit 344.

[0271] The humidification device 352 includes a tank device 354 for cleaning fluid. The tank device 354 is arranged on the cleaning head 342.

[0272] A flow area 356 is assigned to the tank device 354. A sensor device corresponding to the sensor device 126 is located at the flow area 356. The same reference numerals are used for the same elements.

[0273] From the flow area 356, one or more lines 358 lead to a nozzle device 360, by means of which the first cleaning roller unit 344 can be supplied with cleaning fluid.

[0274] The sensor device 126 is in signal-effective connection with an evaluation device 362, which corresponds to the evaluation device 134.

[0275] The sensor device 126 can be used to determine whether the tank device 354 is empty. This is indicated on a display device 364, which is located on the cleaning head 342.

[0276] It is also possible for a transmitter 366 to be controlled via the evaluation device 362 in order, for example, to indicate to a mobile device such as a smartphone the filling level of the tank device 354 for cleaning fluid or to issue a warning message.

[0277] A removably mounted tank device 368 for dirty fluid is also located on the cleaning head 342. Dirty fluid, which is detached or sucked away by the first cleaning roller unit 344, is coupled into the tank device 368.

[0278] In principle, it is also possible for sweepings, for example, to be transported into the tank device 368 via a ramp 370.

[0279] A probe device corresponding to the probe device 310 is assigned to the tank device 368. At least two electrodes protrude into a receiving space of the tank device 368. The corresponding probe device 310 is in fluid communication with the evaluation device 362.

[0280] This makes it possible to determine the filling level of the tank device 368 and, in particular, to determine whether a certain filling level has been reached.

[0281] The evaluation device 362 is connected for signaling purposes to a display device 372, which is associated with the probe device 310. The display device 372 is arranged on the cleaning head 342. It indicates (visually and / or acoustically) whether the specified filling level for the tank device 368 has been reached.

[0282] A corresponding status signal or warning signal, for example for a smartphone or the like, can also be initiated via the 366 transmitter.

[0283] The surface cleaning machine 340 is, for example, parked or moves to a station (in particular a charging station) when it is detected that the tank device 354 is empty and / or the tank device 368 has reached its specific filling level.

[0284] Otherwise, the probe device 310 or the sensor device 126 functions in conjunction with the evaluation device 362 as described above with reference to the evaluation device 134. List of reference symbols

[0285] 10Surface cleaning machine (first embodiment) 12Device body 14Cleaning head 16Surface to be cleaned 18Cleaning roller unit 20Longitudinal axis 22Holding rod device 24Holding rod 26(Hand)grip 28Drive motor 30Housing 32Holder 34Tank device for cleaning fluid 38Valve device 39Filter device 40Fluid line 42Filling 44Battery device 46Motor axis 48Pivot axis 50Double arrow 52Inner sleeve 54Outer sleeve 56Pivot bearing 58Rotation axis 60Cleaning roller holder 62Holding area 64Receiving chamber 66Tank device for dirty fluid 70Shaft 72First part 74Second part 76Intermediate area 78Sleeve 80First Front end 82Second front end 88Accommodation space 100Holding position 102Flap 106Pivot bearing 108Direction 110Wiper guide device 112Inlet opening 114Cross section 116Holding device 118Outlet 120Connection 122Flow area 124Flow direction 126Sensor device 128First electrode 130Second electrode 132Wall 134Evaluation device 136aLine 136bLine138ASIC 140Display device 142Optical display 144Transmitter 146Remote control, mobile device 210Surface cleaning machine 212Cleaning head 214Head body 216First cleaning roller unit 218Second cleaning roller unit 220Carrier 222Filling 224Surface to be cleaned 226First rotation axis 228Second rotation axis 230Drive device 232First drive 234Second drive 236First rotation direction 238Second rotation direction 240First area 242Area 244Second area 246Adjustment device 248First feed direction 250Second feed direction 252Joint 254Retaining rod device 256Pivot axis 258Proximal end 260Bail handle 262Distal end 264Battery device 266Tank device for cleaning fluid 268First outlet opening device 270Second outlet opening device 272First sweeping element 274Second sweeping element 276Longitudinal direction 278Blower device 280Channel 282Channel 284First inlet opening device 286Second inlet opening device 288Tank device forDirty fluid 290 Tank device for dirty fluid 296 First inlet opening device 298 Second inlet opening device 300 First inlet opening device 302 Second inlet opening device 304 Scraper 306 Scraper 310 Probe device 312 First electrode 314 Second electrode 316 Receiving space 318 Tank bottom 320 Liquid level 322 Specific filling level 324 Connection 326 Connection 328 Display device 330 Optical and / or acoustic element 332 Cover wall 334 Level 340 Surface cleaning machine 342 Cleaning head 344 First cleaning roller unit 346 First rotation axis 348 Second roller unit 350 Second rotation axis 352 Humidification device 354 Tank device for cleaning fluid 356 Flow range 358 Line 360 ​​Nozzle device 362 Evaluation device 364 Display device 366 Transmitter 368 Tank device for dirty fluid 370 Ramp 372 Display device

Claims

1. Surface cleaning machine, comprising a cleaning head (212; 342) having at least one cleaning roller unit (216, 218; 344) which is driven for rotary movement, a tank device (288; 368) for dirty fluid and a probe device (310) for determining a degree of fill (322) of the tank device (288; 368) for dirty fluid, wherein the probe device (310) is configured as an electrode device and comprises a first electrode (312) and a second electrode (314) in spaced relation to the first electrode, which electrodes project into a receiving space (316) of the tank device (288; 368) for dirty fluid, characterized in that the first electrode (312) and the second electrode (314) are fixedly connected to a holder (212; 342) for the tank device (288; 368) for dirty fluid, wherein the tank device (288; 368) for dirty fluid is releasable from the holder (212; 342).

2. Surface cleaning machine in accordance with claim 1, characterized in that the probe device (310) is configured as a resistance measuring device.

3. Surface cleaning machine in accordance with claim 1 or 2, characterized by at least one of the following: - the electrode device is arranged and configured such that a particular degree of fill (322) of the tank device (288; 368) for dirty fluid is detectable; - provision is made for the electrode device to have a direct current or a direct voltage applied thereto.

4. Surface cleaning machine in accordance with any one of the preceding claims, characterized in that the probe device (310) is operatively connected to an evaluation device (134) for signal communication therewith, in particular with at least one of the following: - the evaluation device (134) controls an indication device (328) and / or a transmitter (144); - the evaluation device (134) initiates a warning signal for the indication device (328) and / or the transmitter (144) when the reaching of a particular degree of fill (322) is detected; - the evaluation device (134) checks a degree of fill of the tank device (66; 288) for dirty fluid via a resistance determination: - the evaluation device (134) controls the probe device (310) using, in particular, a direct current signal or a direct voltage signal; - the evaluation device (134) comprises a filter device which checks for variations with time in signals of the probe device (310), in particular wherein the filter device is configured such that temporary sloshing of dirty fluid in the tank device (66; 288) for dirty fluid is recognizable; - the evaluation device (134) turns off a drive to the at least one cleaning roller unit (216, 218) and / or a transfer or transferability of cleaning liquid when a particular degree of fill (322) is detected at the tank device (66; 288) for dirty fluid; - the evaluation device (134) prevents rotary drive to the at least one cleaning roller unit and / or suction operation if, when starting operation of the surface cleaning machine, the particular degree of fill (322) is detected; - the indication device (328) is arranged at a hand grip (260) via which the cleaning head (212) is guidable by a user, and / or the indication device (328) is arranged at the cleaning head (342).

5. Surface cleaning machine in accordance with any one of the preceding claims, characterized by a first cleaning roller unit (216; 344) and a second roller unit (218; 348) in spaced relation to the first cleaning roller unit (216; 344), wherein the tank device (288; 368) for dirty fluid is positioned between the first cleaning roller unit (216; 344) and the second roller unit (218; 348), in particular with at least one of the following: - the second roller unit is a second cleaning roller unit (218) or is a sweeping roller unit (348), and, in particular, provision is made for the first cleaning roller unit (216; 344) and the second roller unit (218; 348) to be driven in counterrotation; - a cover wall (332) is provided which is connected to the cleaning head (212) and which covers the tank device (288) for dirty fluid, in particular wherein electrodes of the probe device (310) are arranged at the cover wall (332) and in particular are fixedly connected to the cleaning head (212), and / or that electrodes (312, 314) of the probe device (310) project, in a direction transverse to a plane (334), from the cover wall (332) into a receiving space (316) of the tank device (288) for dirty fluid, wherein a first axis of rotation (226) of the first rotary roller unit (216) and a second roller axis (228) of the second roller unit (218) lie in said plane (334).

6. Surface cleaning machine in accordance with any one of claims 1 to 4, characterized in that the tank device (288) for dirty fluid is releasably arranged at a holding rod device (22) at which the cleaning head (14) is located.

7. Surface cleaning machine in accordance with any one of the preceding claims, characterized in that the surface cleaning machine is configured as a self-propelled and self-steering apparatus.

8. Surface cleaning machine in accordance with any one of claims 1 to 5, characterized in that the surface cleaning machine is configured as a hand-guided apparatus which comprises, in particular, a holding rod device (254) at which the cleaning head (212) is located.

9. Surface cleaning machine in accordance with any one of the preceding claims, characterized by a wetting device by which the at least one cleaning roller unit (216, 218; 344) and / or a surface (16; 224) to be cleaned are capable of having cleaning liquid applied thereto, wherein the wetting device comprises a tank device (34; 266; 354) for cleaning liquid, and in particular characterized by a flow-through region (122; 356) for cleaning liquid through which cleaning liquid which is provided by the tank device (34; 266; 354) for cleaning liquid flows when it is fed to at least one cleaning roller unit (18; 216, 218; 344) and / or to a surface to be cleaned (16; 224), and wherein arranged at the flow-through region (122; 356) is a sensor device (126) which determines the presence of cleaning liquid in the flow-through region (122; 356).

10. Surface cleaning machine in accordance with claim 9, characterized by at least one of the following: - the flow-through region (122; 356) is formed at a tube portion or a hose portion; - the flow-through region (122; 356), under the normally intended conditions of use of the surface cleaning machine, is arranged below the tank device (34; 266; 354) for cleaning liquid, relative to the direction of gravity (g); - the flow-through region (122) is arranged downstream of a port (120) for the tank device (34) for cleaning liquid, relative to a flow direction of cleaning liquid; - a holder (32) is provided to which the tank device (34) for cleaning liquid is in particular releasably held, in particular wherein a port (120) for the tank device (34) for cleaning liquid is arranged at the holder (32) and / or the flow-through region is arranged at the holder (32); - a capability of a flow-through region (122) to have liquid flowing therethrough is coupled to a rotary drive of the at least one cleaning roller unit (18), and / or the flow-through region (122) is located upstream of a valve device (38) for transferring cleaning liquid to the at least one cleaning roller unit (18) and / or the surface (14) to be cleaned; - the sensor device (126) is configured as a resistance measuring device.

11. Surface cleaning machine in accordance with any one of claims 9 or 10, characterized in that the sensor device (126) is configured as an electrode device, and in particular in that provision is made for the electrode device to have a direct current or a direct voltage applied thereto.

12. Surface cleaning machine in accordance with claim 11, characterized in that the sensor device (126) comprises a first electrode (128) and a second electrode (130) in spaced relation to the first electrode (128), wherein the first electrode (128) and the second electrode (130) project into the flow-through region (122), in particular with at least one of the following: - the first electrode (128) and the second electrode (130) are located in a wall (132) of the flow-through region (122) and are in particular injection moulded thereinto; - the first electrode (128) and / or the second electrode (130) are formed as metal pins.

13. Surface cleaning machine in accordance with any one of claims 9 to 12, characterized in that it is determinable via the sensor device (126) whether the tank device (34; 266; 354) for cleaning liquid is empty, wherein the emptying of the tank device (34; 266; 354) for cleaning liquid being inferred from the absence of cleaning liquid in the flow-through region (122; 356).

14. Surface cleaning machine in accordance with any one of claims 9 to 13, characterized in that the sensor device (126) is operatively connected to an evaluation device (134) for signal communication therewith, in particular with at least one of the following: - the evaluation device (134) determines a degree of fill of the tank device (34; 266; 354) for cleaning liquid from sensor data of the sensor device (216); - the evaluation device (134) controls the sensor device (126); - the evaluation device (134) is operatively connected to an indication device (140) and / or a transmitter (144), for signal communication therewith; - the evaluation device (134) initiates a warning signal when the tank device (34; 266; 354) for cleaning liquid is detected as being empty; - the evaluation device (134) turns off a rotary drive to the at least one cleaning roller unit (18) when the tank device (34; 266; 354) for cleaning liquid is detected as being empty.

15. Surface cleaning machine in accordance with claim 14, characterized in that the indication device (140) is arranged at a hand grip (26) via which the cleaning head (14) is guidable by a user, and / or is arranged at the cleaning head (342).