CLEANING DEVICE, IN PARTICULAR FOR ROBOTIC VACUUM CLEANERS

Abstract

A cleaning device comprising a convex transfer surface disposed between a flat nozzle and a rotary brush. The flat nozzle is formed as a multichannel nozzle between the convex transfer surface and the apron with the bevel of the mouth of the multichannel nozzle ranging from 20 to 60 degrees from the horizontal plane. The clearance height between the convex transfer surface and the floor is preferably in the range of 1 to 8 millimetres.

Claims

1. A cleaning device, in particular for robotic vacuum cleaners, characterised in that a convex transfer surface (13) is arranged between a flat nozzle and a rotary brush (1).

2. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterised in that the flat nozzle is designed as a multichannel nozzle (12) between the convex transfer surface (13) and the apron (26) with an inclined orifice of the multichannel nozzle (12) from 20 to 60 degrees from the horizontal plane, wherein the clearance height between the convex transfer surface (13) and the floor (14) being in the range of 1 to 8 millimetres.

3. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterised in that the convex transfer surface (13) continues behind the mouth of the flat nozzle with a rounded approach (30) and ends with a raised trailing edge (25) which is part of the housing (3) of the rotary brush (1).

4. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterised in that the flat nozzle is continuously connected to the spiral housing (24) of the centrifugal fan (7) or at least one side channel by means of a multi-channel air flow straightener (10), whose number of channels connects to the system of individual air ducts (11), which are terminated at the inlet to the multi-channel nozzle (12).

5. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterised in that the cross section of the multichannel nozzle (12) decreases in the range between the mouth of the individual air ducts (11) in the multichannel nozzle (12) and the mouth of the multichannel nozzle (12).

6. The cleaning device, in particular for robotic vacuum cleaners according to claim 2, characterised in that the apron (26) is rounded towards the floor (14) away from the mouth of the multichannel nozzle (12) with a minimum clearance height in the range from 0.5 to 2 millimetres and is smaller than the clearance height of the approach (30) of the convex transfer surface (13) at the lowest point in relation to the floor surface (14).

7. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterised in that the rotary brush (1) is accommodated in a housing (3), which is followed by a vacuum section (2) of the air duct which is connected to the collecting container housing (4) by means of an elastic coupling (22).

8. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterized in that the rotary brush (1) is accommodated in a housing (3) between the vacuum section (2) of the air duct which is connected by means of an elastic coupling (22) to the collecting container housing (4) and an overpressure high-speed part of the air duct of the robotic vacuum cleaner, flowing around the floor surface (14).

9. The cleaning device, in particular for robotic vacuum cleaners according to claim 8, characterized in that the sum of the cross sections of the outlets of the overpressure air ducts (11) of the high-speed section of the air duct is 3 to 40% of the cross section of the vacuum section (2) of the air duct.

10. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterized in th at the cleaning device is suspended on parallel pivoted arms (27) mounted on pins (28) which are rotatably mounted in lugs (29) anchored to the robotic vacuum cleaner structure.

11. The cleaning device, in particular for robotic vacuum cleaners according to claim 1, characterized in that a flat supply channel or at least one side supply channel is arranged between the flat nozzle and the centrifugal fan (7).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] An exemplary embodiment of the invention is shown in the accompanying drawings, in which FIG. 1 shows a partial section of a robotic vacuum cleaner in axonometric view showing the location of key features of the invention, FIG. 2 shows a partial section of a robotic vacuum cleaner showing the position of a cleaning device FIG. 3 shows a partial section of a robotic vacuum cleaner indicating the position of the cleaning device when the robotic vacuum cleaner is driving on a soft surface, FIG. 4 shows a detailed section of a robotic vacuum cleaner cleaning device with a rotary brush, a rotary brush housing, a flat multi-channel nozzle, an apron with side plates and a vertically movable hinge, FIG. 5 shows a detailed section of the cleaning device indicating the air flow under the rotary brush blades, FIG. 6 shows schematically the dependence of the change in flow speed on time and the size of the slit under the rotary brush blades, FIG. 7 shows a bottom view of the robotic vacuum cleaner body with indication of the course of the flow velocity under the blades of the rotary brush, FIG. 8 shows a front view of the robotic vacuum cleaner in a horizontal, working position, FIG. 9 shows a side view of the robotic vacuum cleaner in a horizontal, working position, FIG. 10 shows a detailed section of the cleaning device indicating the air flow at a horizontal, working position, FIG. 11 shows a front view of the robotic vacuum cleaner in an inclined, crossing position, FIG. 12 shows a side view of the robotic vacuum cleaner in an inclined, crossing position, FIG. 13 shows a detailed section of the cleaning device indicating the air flow in the inclined, crossing position of the vacuum cleaner. FIG. 14 shows a detailed embodiment of a robotic vacuum cleaner cleaning device when working on a carpet at a stage where dirt comes into contact with the rotary brush, FIG. 15 shows a detailed embodiment of a robotic vacuum cleaner cleaning device when working on a carpet at a stage where dirt is carried in the space between rotary brush blades and rotary brush housing, FIG. 16 shows a detailed embodiment of a robotic vacuum cleaner cleaning device when working on a carpet at a stage when dirt is expelled by the rotary brush blades from the space between the blades into the vacuum section, FIG. 17 shows schematically a robotic vacuum cleaner cleaning device between the air duct and rotary brush in an exploded view, FIG. 18 shows a multi-channel nozzle in partial section, and FIG. 19 shows an exploded view of a centrifugal regulator with a side channel.

DETAILED DESCRIPTION OF THE INVENTION

[0057] The present invention relates in particular to a robotic vacuum cleaner comprising a partially encapsulated rotary brush 1. driven by an electric motor 8, which is controlled by a control unit in relation to the power input of the electric motor 8 driving a centrifugal fan 7, a vacuum section 2 of air ducts connected to the housing 3 of the rotary brush 1 at one end, and which is connected at the other end via an elastic coupling 22 to the housing of the dirt collection container 4, which is connected via an air filter 5 to an inlet air duct 6 of a centrifugal fan 7 provided with an impeller 46 with blades that are slightly bent backwards and driven by the electric motor 8. The centrifugal fan 7 is encapsulated in a spiral housing 24 with an inlet duct 49 and a side duct 47 with an air outlet 9, and connected to a multi-channel airflow straightener 10 of the air flow, the number of its channels corresponding to the number of outlets to which the same number of air ducts 11 with a small hydraulic dimension is connected at one end, which are on the side of the centrifugal fan 7 connected to the multichannel straightener 10 by a glued joint and at the other end they are mounted in the same number by conical shoulder into recesses in the upper part 12a and lower part 12b in the circular part of air ducts of the air ducts of the flat multichannel nozzle 12, By means of shaping of air ducts a connection to the same number of flat apertures which form the flat multi-channel nozzle 12 is thereby created. The bar 40 with the holes which serve to pass the air ducts 11 serves as a cap to connect the upper part 12a and the lower part 12b of the flat multichannel nozzle 12.

[0058] Alternatively, instead of a multi-channel straightener 10 with a large number of air ducts 11, one straight flat supply duct or at least one side supply duct with a larger cross-section can be used to connect the spiral housing 24 and the flat nozzle, wherein this technical solution provides also significantly higher outlet air velocity than the speed of the intake vacuum air.

[0059] The spiral housing 24 of the centrifugal fan 7 can be replaced by a side channel 47 or a pair of side channels, which are generally arranged below the impeller blade of the centrifugal fan 7. This saves the space of the entire device and, given the dimensions of the centrifugal fan 7, higher static outlet air pressures are achieved.

[0060] The flat multi-channel nozzle 12, which is shown in FIG. 17 and FIG. 18, is formed by an upper part 12a, which is detachably connected by a rod 45 to the housing 3 of the rotary brush 1 and a lower part 12b, which are closed at the side by side plates 41 and connected by connecting elements 42, and is connected to one side of the convex transfer surface 13, which at the other end intersects the inner surface of the housing 3 of the rotary brush 1 driven by the drive motor 23 and thus forms a raised trailing edge 25 of the convex transfer surface 13.

[0061] The apron 26 with side plates 41 is arranged below the flat multi-channel nozzle 12. The whole assembly is suspended on pivoting arms 27, which are hinged by means of pins 28 to holes in the lugs 29 on the body of the robotic vacuum cleaner.

[0062] The principle of the air recirculation in a robotic vacuum cleaner consists in maintaining a constant flow and total pressure in the entire system, but with changing flow velocities and with analogously changing static and dynamic pressures within the flow. The air ducts are divided into a vacuum low-speed subsystem, which comprises a housing 3 of a rotary brush 1 with the rotary brush 1 itself driven by an electric drive motor 23, and a high-pressure overpressure subsystem comprising a system of air ducts 11 having a small hydraulic size.

[0063] The overpressure high-speed subsystem feeds the high-velocity flow into the flat multi-channel nozzle 12 formed by a series of flat outlets, where the flow is further accelerated by reducing the outlet cross-section. Furthermore, the flow is fed along the surface of the convex transfer surface 13 close to the cleaned floor surface 14. After reaching the transfer line 15, where the high-velocity overpressure flow 17 is closest to the surface of the floor 14, the high-velocity overpressure flow layer 17 has a greater thickness than at the mouth of the outlet openings of the flat multichannel nozzle 12. The increase in air layer thickness as the convex surface 36 is flowed-around, is caused in an undesirable manner by sucking 18 into the lower static pressure region that accompanies the high velocity overpressure flow 17. The rate of increase in air layer thickness is directly proportional to the length of the trajectory that the flowing air must travel along the surface of the convex transfer surface 13 from the flat multichannel nozzle orifice to the transfer line 15 because the flowing layer is exposed to ambient air along the entire length of the trajectory. To limit such growth, an apron 26 with side plates 41 is designed, wherein the side plates 41 limit the penetration of ambient air to the surface of the convex transfer surface 13, and thus limit the degree of undesired suction 18 and thus also the increase in the thickness of the air layer.

[0064] Upon reaching the transfer line 15, the high velocity overpressure flow 17 changes the flowed-around surface from the convex transfer surface 13 to the floor surface 14, because said floor surface 14 forms in the transfer line 15 a tangent surface of the convex transfer surface 13. At the same time, the sign of the differential of the static pressures acting on the high-velocity flow layer changes in the transfer line 15.

[0065] Said static pressure differential arises from the fact that on the solid surface side an overpressure from the free atmosphere side acts on the flowing air layer characterized by a higher dynamic and lower static pressure, which presses the flowing layer against the solid surface.

[0066] The high-velocity overpressure flow 17, entraining dirt particles, flows around the cleaned floor surface 14 against the blades 16 of the rotary brush 1, which rotates with the circumferential velocity vector opposite at a lower dead centre than the high velocity overpressure flow vector 17, wherein its speed at a given cross section corresponds to a circumferential velocity of 5 - 10% of the velocity of the high-velocity overpressure flow 17. The dirt particles together with any large objects 21 which have been picked up by the blades 16 of the rotary brush 1 find themselves together with the counter-moving particles entrained by the high velocity overpressure flow 17 in strongly turbulent flow upon contact of the high-speed overpressure flow 17 with the blades 16 of the rotary brush 1 and are carried by the rotary brush 1 between adjacent pairs of blades 16 of the rotary brush 1 into the vacuum section 2 of the air duct and carried by slow flowing air into the dirt collection container 4, where they are stopped by an air filter 5.

[0067] A pair of adjacent blades 16 of the rotary brush 1 and the inner wall of the housing 3 of the rotary brush 1 during its rotation form a temporary closure of the chamber 31 at the moment of passing through the housing 3, where due to a strong turbulence and vortex formation dissipation of the kinetic energy and increase of its static pressure take place, so that at the entry of the slowed down turbulent air 39 into the space of the vacuum section 2 of the air duct the flow has comparable velocity and pressure parameters as are naturally developed in the vacuum section 2 of the air duct by the centrifugal fan 7.

[0068] The connection between the operation of the overpressure and low-pressure air subsystem means that the two air subsystems are not only structurally but also functionally connected by a partially encapsulated rotary brush 1, thus representing the first aspect of synergistic interaction of the high velocity overpressure flow 17 and the rotary brush 1 itself.

[0069] It is precisely the location of the rotary brush 1 with the blades 16 between the vacuum section 2 of the air duct and the high-velocity overpressure flow 17 flowing around the floor surface 14, which allows the desired high velocity differential between the low-pressure and overpressure flow to be used.

[0070] In a preferred embodiment, the ratio between the flow velocity at the mouth of the flat multichannel nozzle 12 and the velocity in the vacuum section 2 of the air duct is 16: 1, more precisely, the flow velocity in the vacuum section 2 of the air duct is 5 m / s and at the mouth of the flat multichannel nozzle 12 80 m / s.

[0071] It is clear that without the forced deceleration which takes place inside the housing 3 of the rotary brush 1, the speed could not be reduced at short distances between the transfer line 15 and the vacuum section 2 of the air duct, because in a natural way, i.e. by friction between the high velocity flow and ambient atmosphere, the speed compensation would require the distance about 500 mm.

[0072] The low flow rate in the vacuum section 2 of the air duct is dictated by the need for sufficient permeability of the vacuum section 2 of the air duct, because all dirt particles including large objects 21 passing under the robot body must have enough space to pass safely through the vacuum section 2 of the air duct to the collecting container 4 which is housed in a shaft with a wall 32. In contrast, in the case of an overpressure air duct 11, no such restriction exists. For this reason, the cross-section of the overpressure air duct 11 or the sum of the cross-sections of the individual overpressure air ducts and their outlet in the flat multichannel nozzle 12 can be reduced in comparison with the cross-section of the vacuum section 2 of the air duct. In a preferred embodiment, the sum of the cross-sections of the outlets of the overpressure air ducts 11 is about 5% of the cross-section of the vacuum section 2 of the air duct. The result is a desirable increase in flow rate which, despite a slight deceleration during the flow around the convex transfer surface 13 due to friction with ambient air accompanied by turbulences 35, positively affects the cleaning effect on the floor surface 14 because the high velocity flow generates an area of reduced static pressure above the floor surface 14 and thus causes the desirable upward suction 19, which also releases otherwise inaccessible dirt from the space between the carpet fibres.

[0073] For the effectiveness of the cleaning effect, the angle of the mouth of the flat nozzle or the multichannel nozzle 12, which it encloses with the floor surface 14, is also important. The increase in this angle is associated with an extension of the trajectory that the air must travel between the mouth of the multichannel nozzle 12 and the transfer line 15. The air velocity decreases due to the turbulence 35 and the volume of the air sucked in and the thickness of the air layer in the transfer line 15 increase due to the undesired suction 18.

[0074] The upper limit of the angle is limited by the condition that the separation indicated by the separation line 37 does not take place before the air reaches the raised trailing edge 25. This is related to the ratio of the thickness of the flowing air layer to the radius of the convex transfer surface 13. The lower is this ratio, the sooner the air separates from the convex transfer surface 13, and the lower is the upper limit of the angle of the mouth of the flat nozzle or the multi-channel nozzle which it forms with the floor surface 14.

[0075] The lower limit of this angle is limited by two factors. In the case of a multi-channel nozzle 12, the individual air streams need to be combined into one stream at the level of the transfer line 15. This depends on the length of the trajectory, the size of the gaps between the outlets of the individual channels and the shaping of the ends of the individual channels, which may be designed to be tapering or widening. In the case of all flat nozzles, the smallest angle is given by the fact that the nozzle body and the adjoining apron 26 do not represent an obstacle for the robotic vacuum cleaner, for example when crossing unevenness or sills.

[0076] Beyond the traditional technical task of the rotary brush 1, which consists in collecting coarser dirt from the floor surface 14, tapping the cleaned floor, especially carpets and transporting loose dirt to the vacuum section 2 of the air duct, the rotary brush 1 with blades 16 in this preferred embodiment of the present invention serves as a flow rate moderator between the high - speed flow from the overpressure subsystem providing a sufficient cleaning effect and the low-speed vacuum subsystem with a large cross-section, enabling the transport of even large particles of dirt to the collecting container 4.

[0077] The transfer line 15, on which the high-velocity overpressure flow around the convex transfer surface 13 is closest to the floor surface 14 and changes the flowed-around surface from the convex transfer surface 13 to the floor surface 14, must be as close as possible to the rotary brush 1 with blades 16, so that the highest possible number of dirt particles released from the floor surface 14 by the high-speed overpressure flow are conveyed due to the inertial force up to the blades 16 of the rotary brush 1. In particular, high-density particles, when released from the surface, move along a trajectory similar to a ballistic curve, because the flow velocity that set them in motion decreases rapidly, although it still far exceeds the velocity of these particles. The clearance height of the convex transfer surface 13 is most often in the range of 1 to 8 millimetres and also depends on the vertical dimension of the flat nozzle, because in the case of a thin layer of air washing the convex transfer surface 13 which would be too far from the floor 14, the air flow would not be transferred from the convex transfer surface 13 to the floor 14, the air would flow up to the raised trailing edge 25 and the system would not work.

[0078] At the same time, it is desirable that in the space between the blades 16 and the transfer line 15 the flow rate be as high as possible so that the particles mechanically released by the blades 16 of the rotary brush 1 are deflected upwards into the space of the housing 3 of the rotary brush ­1 by the flow-induced aerodynamic force. In this way, the penetration of said particles through the slit 20 below the transfer line 15 is prevented.

[0079] Since the distance 43 between the lowest level of the convex transfer surface 13 and the lowest level of the rotary brush 1 must be short, the velocity of the high velocity overpressure flow 17 is much higher at the point when it reaches the blade 16 than the velocity of most particles released and agitated by this flow, and at the same time many times exceeds the flow rate in the vacuum section 2 of the air duct. In order to prevent backflow from the vacuum section 2 of the air duct, which would occur due to a large flow velocity differential, the high-speed overpressure flow 17 must be decelerated in a controlled manner, resulting in decelerated turbulent air 39 having a velocity equal to or close to the flow velocity in the vacuum section 2 of the air duct. In the presented preferred embodiment of the present invention, this object is achieved by using the blades 16 of the rotary brush 1 as described above.

[0080] An important characteristic for the function of the robotic vacuum cleaner according to the present invention is the ratio of the sum of the cross-sections of the outlet of the overpressure air ducts 11 of the high-speed part of the air duct, which is 3 to 40% of the cross-section of the vacuum section 2 of the air duct. The upper limit of this range is possible when using low-pressure centrifugal fans.

[0081] Because the robotic vacuum cleaner works on floors autonomously, it must be able to overcome vertical obstacles such as carpets, skirting boards and thresholds. When the robotic vacuum cleaner overcomes an obstacle, its cleaning elements, which are primarily the rotating brush 1 and the flat multi-channel nozzle assembly 12 with the convex transfer surface 13, change their position relative to the floor surface 14.

[0082] At the moment when the rotary brush 1 and the flat multichannel nozzle assembly 12 with the convex transfer surface 13 are raised, as shown in FIGS. 11 and 12, in whole or in part above the floor surface 14 so that the distance between the transfer line 15 and the floor 14 exceeds the thickness of the flowing air layer, the high-speed overpressure flow 17 from the multichannel nozzle 12 flowing around the convex transfer surface 13 does not change the flowing surface to the floor surface 14 but flows around the convex transfer surface 13 up to the raised trailing edge 25, which directs the flow directly into the housing 3 of the rotary brush 1. This prevents air from escaping into the atmosphere and swirling dirt on the floor surface 14.

[0083] The apron 26 with side plates limits the unwanted suction 18 of air which is sucked from the ambient atmosphere into the reduced pressure region caused by the high velocity flow from the flat multi-channel nozzle 12 and by the flow-around the convex transfer surface 13.

[0084] The apron 26 with the side plates 41 encloses the space behind the convex transfer surface 13 and is characterized by a smaller clearance height than corresponds to the distance of the transfer line 15 from the floor surface 14.

[0085] The compensation for the increase in air volume due to its desired suction 19 and unwanted suction 18 takes place in a controlled manner by escaping pulsating air 38 through a periodically generated by the pulsating gap 44 under the blades 16 of the rotary brush 1 so that the flow velocity under the rotary brush 1 decreases to 0 m / s still under the body of the robotic vacuum cleaner. Due to the fact that even within this flow the static pressure is lower than in the surrounding atmosphere and the flow stops under the robotic vacuum cleaner, there can occur no leakage of impurities into the surrounding atmosphere.

[0086] There are two other aspects of the synergistic action between the rotary brush 1 and the high-speed overpressure flow 17.

[0087] The first of them is related to the usability of the rotary brush 1, more precisely to its circumferential speed. The higher is the circumferential speed of the rotary brush 1, the higher the effect on the dirt and the cleaning effect have the blades 16. More specifically, a positive effect has the higher number of interactions between the blades 16 and the floor surface 14 per unit time, because increases the probability of dirt intervention and the intensity of dirt release from carpet fibres.

[0088] In the prior art of robotic vacuum cleaners, the speed of rotation of the rotary brush and thus its circumferential speed is limited, because the speed of vacuum flow along the brush is low for previously described reasons and behind the brush there are only a mechanical apron which must maintain a certain ground clearance 30 above the floor surface, so as not to prevent the robot from moving and overcoming vertical obstacles.

[0089] In the present preferred embodiment, the mechanical apron is replaced by the pneumatic effect of a counter-rotating high-speed overpressure flow 17, which completely seals the space between the transfer line 15 and the floor surface 14. Thanks to the described sealing means, it is thus possible to significantly increase the rotation speed of the rotary brush 1 in comparison with the prior art. The higher the speed of the high-speed overpressure flow 17, the higher the rotation speed of the rotary brush 1 can be used. That is, each increase in the speed of the high-speed overpressure flow 17 has a multiplier effect, because the circumferential speed of the rotary brush 1 and the consequent increase in the cleaning effect is also increased.

[0090] The second synergistic effect relates to the effect of the blades 16 on the particles trapped between the carpet fibres. The blades 16 strike dirt particles on the surface, in particular on the surface of the carpet, at a frequency which, at normal speeds of 1000 rpm and about 17 revolutions per second, corresponds to a frequency of about 100 strokes per second in a conventional paddle brush. At this frequency, the fibres of the carpets with the trapped dirt particles are hit and bent, causing them to be mechanically released and a considerable part is moved closer to the surface or jumps to the surface. These particles are then cleaned either directly or secondarily by the high-speed overpressure flow 17 on the basis of the previously described mechanisms.

[0091] The flat multi-channel nozzle 12, the apron 26 with side plates 41 reducing the air intake, the convex transfer surface 13, the rotary brush 1 with the electric motor 8 and gearbox, the housing 3 of the rotary brush 1 with its vacuum section 2 of the air duct, which is by an elastic coupling 22 connected to the wall 32 of the housings of the collecting container 4, are suspended as a whole on parallel pivoted arms 27 suspended on pins 28 on lugs 29 of the robotic vacuum cleaner structure.

[0092] This suspension compensates for changes in the ground clearance of the robotic vacuum cleaner that occur due to the different hardness of the surfaces on which the robotic vacuum cleaner works, such as a wooden floor or a soft carpet. With the usual density of a robotic vacuum cleaner, the usual difference is 3 - 4 mm.

[0093] The position of the self-levelling structure on a hard surface is shown in FIG. 2. On the hard surface, the relative vertical position of the drive wheels 33 and the auxiliary wheel 34 with respect to the self-levelling structure, in particular with respect to the vertical position of the blades 16, more precisely to the vertical position of the axis of the rotary brush 1 where the blades 16 of the rotary brush 1 move closely slidably against the floor surface 14 is clearly defined, and the apron 26 with the side plates has a clearance height of about 1 mm above the floor surface 14.

[0094] FIG. 3 shows the position of said structure on a soft surface, where the drive wheels 33 and the auxiliary wheel 34 are immersed in the soft surface of the floor 14, and therefore the ground clearance of the robotic vacuum cleaner is reduced. On a soft surface, the self-levelling structure, which is suspended on the swing arms 27, slides into the body of the robotic vacuum cleaner and rests on the sliding surface of the apron 26 and the rotating blades 16 of the rotary brush 1, which are immersed about 1 mm below the carpet surface.

INDUSTRIAL APPLICATION

[0095] The present invention can be used in particular for robotic vacuum cleaners, which aim to supply fast-flowing air from the spiral housing of a centrifugal fan of a robotic vacuum cleaner directly to the floor surface.

TABLE-US-00001 List of Reference Characters 1 rotary brush 2 vacuum section 3 housing 4 collection container 5 air filter 6 inlet air duct 7 centrifugal radial flow fan 8 electric motor 9 air outlet 10 multichannel straightener 11 air duct 12 multichannel nozzle 12a upper part 12b lower part 13 convex transfer area 14 floor 15 line 16 blade 17 high-speed overpressure flow 18 unwanted suction 19 desirable suction 20 gap 21 large objects 22 elastic coupling 23 drive motor 24 spiral housing 25 raised trailing edge 26 apron 27 pivoted arm 28 pin 29 lug 30 approach 31 chamber 32 wall 33 drive wheel 34 auxiliary wheel 35 turbulence 36 circulation around a convex surface 37 separation lines 38 escaping pulsating air 39 decelerated turbulent air 40 bar 41 side plate 42 fasteners 43 distance 44 pulsating gap 45 rod 46 impeller 47 side channel 49 input channel