INTAKE PROTECTION DEVICE AND CLEANING DEVICE HAVING SUCH A SUCTION PROTECTION DEVICE

Abstract

A suction protection device for an air duct arrangement between a liquid collection area and a negative pressure source of a cleaning device is disclosed. The suction protection device includes a sealing body, sealing the air duct arrangement when positioned in its closed position and releasing the air duct arrangement when positioned in its open position to suck air out of the liquid collection area. The suction protection device further includes a load actuator configured to generate a pulling load via which the sealing body may be forced into the closed position and/or the open position.

Claims

1. A suction protection device for an air duct arrangement between a liquid collection area and a negative pressure source of a cleaning device comprising: a sealing body, sealing the air duct arrangement when positioned in a closed position and releasing the air duct arrangement when positioned in an open position to suck air out of the liquid collection area and a load actuator to generate a pulling load via which the sealing body is capable of being forced into the closed position and/or the open position.

2. The suction protection device according to claim 1, wherein the sealing body seals the air duct arrangement in its closed position such that liquid and preferably air are prevented from flowing from the liquid collection area to the negative pressure source.

3. The suction protection device according to claim 1, wherein the load actuator is configured to force the sealing body into the closed position and/or the open position, depending on: another load being applied to the sealing body; and/or a position of the sealing body relative to the load actuator; and/or a position of the sealing body relative to the open position and/or the closed position.

4. The suction protection device according to claim 1, wherein the load actuator may be activated and/or or deactivated; and wherein an amount of the pulling load of the load actuator may be adjustable.

5. The suction protection device to according to claim 1, further comprising a detection device to generate a signal, wherein, based on the signal: the load actuator may be activated and/or deactivated to generate pulling load; and/or the load actuator may be controllable to generate pulling load; and/or another force may be changeable by the sealing body; and/or the position of the sealing body may be changeable relative to the load actuator; and/or the negative pressure source may be controllable.

6. The suction protection device according to claim 5, wherein the detection device comprises at least an actuatable switch to generate the signal.

7. The suction protection device according to claim 5, wherein the detection device comprises at least one sensor configured to generate the signal, wherein the sensor is: a filling level sensor to detect a liquid level in the liquid collection area; and/or an inclination sensor to detect an inclination of the liquid collection area; and/or a pressure sensor to detect pressure in at least either the liquid collection area, the air duct arrangement and the negative pressure source; and/or a sensor to detect an operating position of the cleaning device.

8. The suction protection device according to claim 1, wherein the load actuator is configured in such a way that the pulling load decreases or increases with increasing distance of the sealing body to the closed position and/or increases or decreases with increasing distance to the open position, wherein preferably the load decrease or increase proceeds disproportionately with the distance.

9. The suction protection device according to claim 1, wherein the pulling load of the load actuator comprises a magnetic force.

10. The suction protection device according to claim 1, wherein the load actuator comprises a mechanical pulling mechanism to generate the pulling load, wherein the mechanical pulling mechanism preferably comprises a hydraulically and/or pneumatically and/or electrically actuatable pulling load.

11. The suction protection device according to claim 1, wherein a suction force, which is being generated in an operative state via the negative pressure source and which is being applied to the sealing body is, at least partially: applied in the direction of the closed position or the open position; and/or applied in the direction or against the pulling load of the load actuator.

12. A floor cleaning device for wet cleaning a cleaning surface, comprising: a liquid collection container with a liquid collection area to collect a liquid, sucked from a cleaning surface; an air duct arrangement; a negative pressure source configured to suck air from the liquid collection area via the air duct arrangement in an operative state, wherein the liquid collection area is underpressurized to suck the liquid; and a suction protection device according to claim 1.

13. The cleaning device according to claim 12, further comprising a guide member to guide the cleaning device, wherein the liquid collection container is disposed on the guide member and is, together with the guide member, adjustable in its length, in particular pivotable, or wherein the liquid collection container at least partly forms the guide member.

14. The cleaning device according to claim 13, further comprising: a cleaning unit, and a joint assembly, which at least comprises a pivot axis and with which the guide member is articulately and about its longitudinal axis connected to the cleaning unit in a torque-transmitting manner.

15. The cleaning device according to claim 14, further comprising at least a tool that is assigned to the cleaning unit and is configured to rest at least in sections on the cleaning surface in an operative state.

Description

[0098] The invention is further explained below with reference to the accompanying drawings. In the drawings:

[0099] FIG. 1 a schematic representation of a suction protection device according to a first implementation;

[0100] FIG. 2 a schematic further representation of the suction protection device according to the first implementation;

[0101] FIG. 3 a schematic representation of a suction protection device according to a second implementation;

[0102] FIG. 4 a schematic further representation of the suction protection device according to the second implementation;

[0103] FIG. 5 a spatially arranged representation of a cleaning device with a suction protection device;

[0104] FIG. 6 an exemplary and schematic sectional view of a suction protection device according to a third implementation in a state arranged on a cleaning device;

[0105] FIG. 7 a detailed representation of the suction protection device according to the third implementation;

[0106] FIG. 8 a detailed view of the suction protection device according to the third implementation in a state inserted into the elongated shaft;

[0107] FIG. 9 a sectional view of the suction protection device according to the third implementation;

[0108] FIG. 10 a further sectional view of the suction protection device according to the third implementation;

[0109] FIG. 11 an exemplary and schematic partial sectional view of a suction protection device according to a fourth implementation in a state arranged on a cleaning device;

[0110] FIG. 12 a sectional view of the suction protection device according to the fourth embodiment; and

[0111] FIG. 13 a further sectional view of the suction protection device according to the fourth implementation.

[0112] FIG. 1 relates to a schematic representation of a liquid collection container 10 of a cleaning device, in which an air duct arrangement 12 is arranged in an upper region. The air duct arrangement 12 is configured as a separation within the liquid collection container 10 and forms an opening 14, which connects the upper region with a liquid collection area 16 of the liquid collection container 10. A liquid 18 is located in a lower region in the liquid collection area 16. Air is arranged above the liquid 18. If the liquid collection container 10 is empty, the liquid collection area 16 is completely filled with air. A suction line 20 leads into the liquid collection container 10 at a lower side of the liquid collection container 10, whereby this is to be understood merely as an example and access may also be provided at another position of the liquid collection container 10. A suction line 20 is set up to guide a liquid and/or air flow and to supply it to the liquid collection container 10. A splash guard 22 is configured between the suction line 20 and the air duct arrangement 12 in order to prevent sucked-in liquid from splashing in the direction of the opening 14.

[0113] A suction connection 22 is configured on an upper side of the liquid collection container 10, which is connected to a negative pressure source not shown. In an operative state, the negative pressure source is set up to pressurize the liquid collection container 10 so that liquid 18 may be sucked into the liquid collection area 16 via the suction line 20. A filter 24 is arranged at the suction connection, which is set up to filter out dirt particles from the sucked-in air so that these cannot enter the negative pressure source. It is provided that the liquid 18 is separated from the liquid and/or air flow drawn in via the suction line 20 in the liquid collection container 10 and collected in the liquid collection area 16. As soon as the liquid 18 in the liquid collection area 16 reaches a predetermined level, the liquid collection container 10 is emptied. For this purpose, the liquid collection container 10 comprises an emptying opening (not shown) for emptying the liquid 18.

[0114] A suction protection device 26 according to a first implementation is arranged on the air duct arrangement 12, which comprises a sealing body 28 in the form of a pivotable flap and a load actuator 30. The sealing body 28 is shown in an open position, because it does not close the opening 14, but releases the air duct arrangement 12 for drawing in air from the liquid collection area 16. This may be recognized by the arrows shown by way of example, which represent the air flow. An open position may be understood as any position in which the sealing body 28 releases the opening 14. The load actuator 30 is set up to generate a pulling load by means of which the sealing body 28 may be urged into the open position and a closed position. In the closed position, the sealing body 28 closes the air duct arrangement 12 in such a way that neither liquid nor air can pass from the liquid collection area 16 to the negative pressure source. In other words, the load actuator 30 presses the sealing body 28 into the closed position and thus against the air duct arrangement 12 in such a way that the opening 14 is closed in a fluid-tight manner.

[0115] For this purpose, a sealing arrangement, preferably made of rubber material, may be provided in the area of the opening 14, against which the sealing body 28 presses in the closed position.

[0116] The load actuator 28 comprises a guide arrangement 29 in the form of a pivot joint, by means of which the sealing body 28 is pivotable between the closed position and the open position. The load actuator 30 is configured as an operable, mechanical pulling mechanism. The pivot joint has a pivot axis A, about which the sealing body 28 is pivotable between the closed position and the open position. In the present case, the pivot axis A is oriented in the plane of the drawing.

[0117] A filling level sensor 32 is configured in the liquid collection area 16 near the air duct arrangement 12, which is configured to measure the filling level of the liquid 18 in the liquid collection area 16. Furthermore, an inclination sensor 34 is arranged on the liquid collection container, which is configured to detect an inclination of the liquid collection container 10 in at least one, but in the present case two, spatial directions. The two sensors 32, 34 may be connected to a control device (not shown) whereby the control device may control the load actuator 30 for generating the pulling load depending on the measured values or signals of the sensors 32, 34.

[0118] FIG. 2 concerns a schematic representation of the liquid collection container 10 with the suction protection device 26 according to the first implementation, wherein the suction protection device 26 is shown in a different state. Compared to FIG. 1, the load actuator 30 pushes the sealing body 28 into the closed position. As a result, the opening 14 of the air duct arrangement 12 is closed in a fluid-tight manner. It is possible that the negative pressure source continues to generate negative pressure via the suction connection 22 and that this is then present in the upper area of the liquid collection container 10. However, the closed position of the sealing body 28 prevents the liquid collection area 16 from being pressurized as well. This means that no liquid or air is drawn in via the suction line 20. Furthermore, the closed position of the sealing body 28 ensures that neither the liquid 18 nor air from the liquid collection area reach the negative pressure source.

[0119] FIG. 3 concerns a schematic representation of a suction protection device 126 according to a second implementation. Compared to FIGS. 1 and 2, the suction protection device 126 has a sealing body 128 which is configured to be ball-shaped or spherical. Furthermore, a guide recess 136 is configured on the sealing body 128, in which a guide arrangement 129 in the form of a guide rod engages. The sealing body 128 is arranged to be displaced on the guide rod 129 between the closed position and the open position. The guide rod 129 guides the sealing body 128 and ensures that the sealing body 128 does not change its orientation relative to the opening 114. A magnetizable material 138 is arranged on the sealing body 128 in a region oriented towards the opening 114. A stop 140 is configured on the guide rod 129, which makes contact with the sealing body 128 in the open position and prevents the sealing body 128 from assuming a position on the guide rod 129 that is impermissibly far from the closed position. A filter 124 is arranged at the suction connection 122, which is set up to filter out dirt particles from the sucked-in air so that these cannot enter the negative pressure source.

[0120] A load actuator 130 in the form of a magnet is arranged in the liquid collection area 116, which is configured to attract the magnetizable material 138. For this purpose, the magnet may be configured as a switchable (electro)magnet and may generate a magnetic force depending on the switching state. The magnetic force may act as the pulling load on the sealing body 128 in order to push it into the closed position depending on the switching state. In the present case, the magnet is configured as a permanent magnet. The distance between the magnetizable material 138 and the magnet is selected for the open position in such a way that the magnet does not cause a sufficiently large pulling load on the sealing body 128 to push the sealing body 128 into the closed position against a suction force acting on it due to the air flow through the negative pressure source. However, if the air flow is deactivated or reduced, for example by deactivating the negative pressure source, the sealing body 128 is pushed into the closed position by the pulling load of the magnet.

[0121] A filling level sensor 132 is configured in the liquid collection area 116 near the air duct arrangement 112, which is configured to measure the filling level of the liquid 118 in the liquid collection area 116. Furthermore, an inclination sensor 134 is arranged on the liquid collection container 110, which is configured to detect an inclination of the liquid collection container 110 in at least one, but in the present case two, spatial directions. The two sensors 132, 134 may be connected to a control device (not shown), whereby the control device may control the load actuator 130 for generating the pulling load depending on the measured values or signals of the sensors 132, 134.

[0122] In FIG. 3, the sealing body 128 assumes the open position. The negative pressure source applies negative pressure to the liquid collection container 110 via the suction connection 122. Due to the open position, air flows past the sealing body 128 through the opening 114. Furthermore, the negative pressure in the liquid collection area 116 draws in liquid and air via the suction line 120. The liquid 118 is separated into the lower region of the liquid collection area 116.

[0123] FIG. 4 concerns a schematic representation of the suction protection device 126 according to the second implementation, wherein the sealing body 128 assumes the closed position. The load actuator 130 in the form of the magnet exerts a pulling load on the magnetizable material 138, which reliably holds the sealing body 128 in the closed position. The magnet may be dimensioned such that the pulling load in the closed position is so great that the liquid collection container 110 may be tilted, whereby the force acting on the sealing body 128 in the direction of the open position due to the liquid 118with a high or also low filling level of the liquid 118is not enough to move the sealing body 128 out of the closed position. The sealing body 128 remains firmly in the closed position and prevents liquid from passing through the opening 114 of the air duct arrangement 112. However, the pulling load may be dimensioned such that a suction force that is to be generated due to the negative pressure source is being applied on the sealing body 128 to force the sealing body 128 from the closed position into the open position against the pulling load. It may be provided that the negative pressure source has a suction mode that can generate a particularly high suction force, which is higher than in a normal suction mode of the cleaning device. As a further example, reference is made to the switchable magnet mentioned above, which is activated when the sealing body 128 is to be held in the closed position or is to be urged into this position, and which is deactivated when the sealing body 128 is to assume the open position.

[0124] FIG. 5 shows a spatially arranged representation of a cleaning device 250 with a suction protection device, which, however, is not visible as it is arranged within the components shown. The cleaning device 250 is configured as a scrubbing-suction machine. The cleaning device 250 comprises a cleaning unit 252 and a guide member 254, which are connected to another in an articulated manner via a joint assembly 256.

[0125] Two brush-like tools 258, 260 are assigned to the cleaning unit 252, which may be driven rotationally and then generate a propulsion effect in a propulsion direction V. For this purpose, each tool 258, 260 is assigned a drive arrangement 262, which also supports the respective tool 258, 260. The cleaning unit 252 comprises a plate-like housing 264, to which the two drive arrangements 262 are attached at a distance from one another. The two tools 258, 260 protrude from the housing 264 on an underside of the cleaning unit 252 and contact a floor surface to be cleaned in an operative state. A vacuum bar arrangement 266 is provided at the rear of the housing 264, which comprises two sealing lips 268 and which is supported relative to the floor surface (not shown) via three support wheels 270 arranged at the rear. The sealing lips 268 are preferably formed from rubber-like material. A design with a single sealing lip or with more than two, for example three, sealing lips may also be provided. At a front side of the housing 264, two upwardly inclined transport rollers 272 are provided on bearing projections 274 on the cleaning unit 250. The transport rollers serve to facilitate handling of the cleaning device 250 according to the invention in a storage position, in which the transport rollers 272 contact the base surface and support the cleaning device 250 relative thereto. A replaceable, U-shaped battery unit 276 is arranged at the rear of the housing 264 at a distance from the floor surface and serves to supply the cleaning device 250 with electrical energy. The guide member 254 has an elongated, hollow configured shaft 278 with an operating arrangement 280 attached to the upper end of the shaft. The operating arrangement 280 comprises two handles 282 with associated operating levers.

[0126] Together with the operating arrangement 280, the guide member 254 forms a T-shape. A central control panel 284 with a display for displaying an operative state of the cleaning device, such as a current charging state, the current rotational speed of the tools 258, 260, filling levels for various liquids such as clean water, dirty water or cleaning liquid, an inclination angle of the guide member 254, a remaining operating time or similar information is provided in the center of the operating arrangement 280. Furthermore, the central control panel may comprise setting instruments for switching on and controlling various operating parameters of the cleaning device 250, such as the rotational speed of the tools 258, 260 or similar information. This may include a detection device in the form of an actuatable switch 285 for actuating the load actuator.

[0127] A freshwater tank 286 and the liquid collection tank 210 are arranged on a front side of the elongated shaft 278. Both containers 286, 210 are attached to the shaft 278 via a respective receiving device and are thus configured to be decoupled from the shaft 278 for filling and emptying. In addition to water, the freshwater tank 286 may be filled with a mixture of water and cleaning liquid. Alternatively, a separate container with cleaning liquid may be provided, which is not shown in the figures. Below the freshwater tank 286, a component not shown in detail is provided for supplying clean water to the cleaning unit 252. At an upper region of the liquid collection container 210, one end of the suction line 220 is coupled thereto. The other end of the suction line 220 is coupled to the cleaning unit 252. The suction line 220 is used to suck air and/or liquid and/or dirt from the vacuum bar arrangement 266 and feed it to the liquid collection container 210. For this purpose, a negative pressure source 288 is provided at a lower end of the elongate shaft 278 in the form of a suction turbine, which is coupled in a manner not shown in detail to the liquid collection container 210 in order to generate a negative pressure therein.

[0128] The joint assembly 256 has a first pivot axis B and a second pivot axis C, the guide member 254 being pivotable forwards or backwards by means of the first pivot axis B and to the left or right, i.e. in a lateral direction, relative to the cleaning unit 252 by means of the second pivot axis C. The joint assembly 256 is configured to be rigid about a longitudinal axis L, so that the guide member 254 is connected to the cleaning unit 252 in a torque-transmitting manner about the longitudinal axis L.

[0129] The cleaning device 250 may comprise a suction protection device according to an embodiment, as already explained above or as will be explained below.

[0130] FIG. 6 relates to an exemplary and schematic sectional view of a suction protection device 326 according to a third implementation in a state arranged on a cleaning device 350. The cleaning device 450 may be the same as shown in FIG. 5. The liquid collection container 310 is arranged on the elongate shaft 378, on which a closable emptying opening 390 for emptying the liquid collection container 310 is configured at an upper end. The emptying opening 390 may additionally function as a connection for a suction line, such as the suction line 220 of FIG. 5, in order to suck in liquid and/or air from the cleaning unit. An operating arrangement 380 is arranged on the elongate shaft 378 as explained above. In the present case, however, the liquid collection container 310 comprises a separately configured connection for connecting the suction line. The liquid collection container 310 has a connection opening 392 on the side, via which it is coupled to an air duct arrangement 312. The air duct arrangement 312 comprises a flange 394, which is coupled in a fluid-tight manner to the connection opening 394 on one side, i.e., on the supply air side, of the air duct arrangement 312. On the other side of the air duct arrangement 312, i.e., on the exhaust air side, a hose connection 322 is configured thereon, which is coupled to a hose 395 arranged within the elongate shaft 378, which in turn is connected to the negative pressure source (not shown). Thus, starting from the negative pressure source, air can be sucked out of the liquid collection area 316 of the liquid collection container 310 via the air duct arrangement 312 in an operative state of the cleaning device 350. However, it is necessary that the suction protection device 326 described in more detail below permits this.

[0131] The suction protection device 326 is arranged on the air duct arrangement 312 and has a similar flap-shaped sealing body 328 as explained in connection with FIGS. 1 and 2. The sealing body 328 is mechanically coupled to a load actuator 330 configured as an electric motor. The electric motor is arranged outside the air duct arrangement 312 on the latter and is mechanically coupled to the sealing body 328 for actuating or forcing the same. The sealing body 328 is arranged inside the air duct arrangement 312 and is configured to close, in its closed position, an opening 314 which opens into the flange 392.

[0132] FIG. 7 shows a detailed representation of the suction protection device 326 of FIG. 6, which is configured on the air duct arrangement 312. The flange 394 comprises the opening 314, which may be elongated or oval. Further, a flange stop 397 is configured on the flange, which serves the purpose of sealing between the flange 394 and the connection opening 392 against the surroundings. The load actuator 330, which is configured as an electric motor, is arranged on the upper side of the air duct arrangement. The load actuator 330 is mechanically coupled to the sealing body 328 via a lever mechanism 396, which is arranged inside the air duct arrangement 312. A supported spring 398 opposite the air duct arrangement 312 engages with the lever mechanism 396, forcing the sealing body 328 into the closed position. Thus, the load actuator 330 is supported by the spring 398 when being urged into the closed position, in contrast, it has to work against the effect of the spring 398 when being urged into the open position. The spring 398 could also act on the sealing body 328 in the opposite way. Furthermore, the spring 398 could be omitted.

[0133] The suction protection device 326 is configured in a modular manner and may be inserted into the elongate shaft 378. In order to insert the suction protection device 326 into the elongate shaft 378, the latter may, for example, be configured from at least two halves that may be coupled to one another or from a sufficiently large opening.

[0134] FIG. 8 shows the suction protection device 326 of FIGS. 6 and 7 in a state in which they are inserted into the elongate shaft 378. The flange 394 is coupled to the connection opening 392, wherein an additional seal may be provided between the two to seal against the surroundings. The load actuator 330 engages the lever mechanism 396 on the flap-shaped sealing body 328 and is arranged to pivot it via an actuator axis M between the closed position and the open position shown. At a lower end, the air duct arrangement 312 is coupled to the hose 395.

[0135] FIGS. 9 and 10 show the suction protection device 326 of FIGS. 6 to 8 in a sectional view along line D-D in the viewing direction from above, i.e., starting from the operating arrangement (not shown). In FIG. 9, the sealing body 328 assumes the open position, so that the opening 314 for sucking air from the liquid collection container 310 is released. In FIG. 10, the sealing body 328 assumes the closed position so that neither liquid nor air from the liquid collection container 310 can pass through the opening 314 at the flange 394. The sealing body 328 is configured as an elongated, curved flap. The outer surface of the curved sealing body 328 substantially coincides with an inner radius of the air duct arrangement 312. The connecting flange 397 is configured on the flange 394. A sealing arrangement may be provided on the sealing body 328 and/or in the region of the opening, which the sealing body 328 presses into the closing body.

[0136] FIG. 11 relates to an exemplary and schematic partial sectional view of a suction protection device 426 according to a fourth implementation in a state arranged on a cleaning device 450. The cleaning device 450 may be the same as shown in FIG. 5. The further implementation differs from the implementation of FIGS. 6 to 10 in that it has a different embodiment of the suction protection device 426 and the air duct arrangement 412, which is similar to that of FIGS. 3 and 4. At the elongate shaft 478, the liquid collection container 410 is shown in a partially sectioned view. The liquid collection container 410 has a receiving curvature 500 to enclose the suction protection device 426, which is attached to the elongated shaft 478. However, a connection port 492 is configured on the receiving curvature 500 to couple the suction protection device 426 to the liquid collection area 416 of the liquid collection container 410 for drawing air. The suction protection device 426 has an air filter 502, via which air may be sucked from the liquid collection container 410 into the suction protection device 426 and is cleaned of dirt particles in the process. The air duct arrangement 412 forms a type of housing of the suction protection device 426 and serves to guide air from the liquid collection container 410 in the direction of the negative pressure source (not shown). As also described above, a hose 495 (not shown) is arranged within the elongated shaft 478 for this purpose, which couples the suction protection device 426 to the negative pressure source for guiding or extracting air. The air duct arrangement 412 forms a closed housing apart from its lower region 504, in which the air filter 502 is arranged. The lower region is configured as a housing part 504 of the air duct arrangement 412 that may be coupled to an upper part. In addition, the multiple parts serve to facilitate the assembly and to remove the couplable housing part 504 from the air duct arrangement 412 and to replace the air filter 502. Two clamping tabs 505 are arranged on the outside of the air duct arrangement 412 to secure the couplable housing part 504 to the air duct arrangement 412. The suction protection device 426 is attached to the elongate shaft 478 by means of screws, although other fastening means may be provided instead or in addition.

[0137] FIG. 12 concerns a sectional view of the suction protection device 426 of FIG. 11, which shows the internal structure of the suction protection device 426. For reasons of better representation, the filter is not shown. The sealing body 428 assumes the open position and thus exposes the circularly configured opening 414 of the air duct arrangement 412 in such a way that air can flow through the air duct arrangement 412 (see arrows shown). The sealing body 428 is attached to a guide arrangement 429 configured as a guide rod, on which it can be displaced between the open position and the closed position and is guided by it. It could be said that the sealing body 428 is attached to the guide rod. A magnetizable material 438, specifically ferrous metal, is arranged on the sealing body 428 in a lower region, whereby this could also be a magnet, for example. A load actuator 430 configured as a magnet, which is arranged on the air duct arrangement 412 centrally to the opening 414 and at a distance therefrom, exerts a pulling load on the magnetizable material 438. The magnet 430 could also be arranged on the sealing body 428, in which case magnetizable material or the like would be arranged on the air duct arrangement 412 in order to interact with the magnet. Furthermore, magnets that are oriented to exert a pulling force on each other could be provided. The magnet 430 is arranged in a recess 508 configured on the air duct arrangement 412 and is held therein by a magnet holder 510. The sealing body 428 is arranged at a distance from the magnet 430, so that the magnetizable material 438 is also at a distance from the magnet 430.

[0138] The air duct arrangement 412 is configured in a tubular form in its interior. An annular web 512, which is configured on the inner wall of this tubular form, supports a sealing ring 514 and, together with this, forms the opening 414. The sealing ring 514 is configured to cooperate with the sealing body 428 in its closed position and to close the opening 414 in a fluid-tight manner. The guide arrangement 429 is configured on a retaining web 516, which has air passages (not shown), to allow air flow through the air duct arrangement 412. The retaining web 516 is configured in a cross shape.

[0139] A hose connection 422 is configured at an upper end of the air duct arrangement 412, which may be coupled directly or via an intermediate piece to a hose 495 in the interior of the elongated shaft 478, which is not shown in detail in FIG. 12.

[0140] The air duct arrangement 412 has intake openings 518 in its lower region 504, in which the filter 502 (not shown) is arranged, so that air from the surroundings of the lower region 504 may be sucked into the air duct arrangement 412 through the intake openings 518. After the sealing body 428 assumes the open position and thus exposes the opening 414, air from the surroundings of the lower region can flow through the intake openings 518, through the opening 414 past the sealing body 428 and past the retaining web 514 to the hose connection 422. The magnet is dimensioned in such a way that the pulling load acting on the sealing body 428 due to the magnetic force cannot force the sealing body 428 into the closed position against the suction force acting on it due to the air flow. Since the magnet 430 is spaced apart from the magnetizable material 438, the pulling load acting on the sealing body 428 due to the magnetic force is comparatively small compared to the closed position in which the magnet 430 is only slightly spaced apart from the magnetizable material 438. The loss of suction force resulting from the pulling load is therefore extremely small. The magnet 430 could also be configured as a switchable magnet. Furthermore, the magnet 430 may be configured as a controllable electromagnet or permanent magnet or as a combination thereof, which does not generate a pulling load in an operative state in which the open position is desired and which does generate a pulling load in a different operative state, in which the closed position is desired.

[0141] FIG. 13 concerns a sectional view of the suction protection device 426 of FIG. 12, in which, however, the sealing body 428 assumes the closed position. For this purpose, the sealing body 428 has been displaced on the guide arrangement 429 in the direction of the opening 414 and now closes it. The magnetizable material 438 is arranged close to the magnet 430, so that the magnet 430 exerts the pulling load on the magnetizable material 438 and thus on the sealing body 428 and pushes it into the closed position. The pulling load is so great that the sealing body 428 is pressed sufficiently firmly against the sealing ring 514 to close the opening 414 in a fluid-tight manner. Thus, neither liquid nor air can pass through the opening 414. Thus, neither liquid nor air can pass through the air duct arrangement 412. In other words, neither liquid nor air can pass from the liquid collection container to the negative pressure source via the air duct arrangement 412.

[0142] In connection with all embodiments, it is understood that the suction protection device may comprise a control device which is set up to control, for example, the load actuator and/or the negative pressure source. Furthermore, the cleaning device may comprise a corresponding control device. This might be configured separately or integrally with a control system of the cleaning device, which controls other components, such as the tools.

[0143] Features and embodiments explained in connection with one of the four implementations are transferable to the other implementations. Furthermore, all features and configurations explained in connection with one of the implementations for suction protection devices may be realized in the cleaning device according to FIG. 5 and vice versa.