Patent Publication Number: US-10779697-B2

Title: Method for adjusting a position of suction lips of a floor cleaning machine and floor cleaning machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of international application number PCT/EP2013/060962 filed on May 28, 2013, which is incorporated herein by reference in its entirety and for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a method for adjusting a position of suction lips of a floor cleaning machine relative to a floor to be cleaned, wherein a first suction lip and at least one second suction lip located at a distance therefrom, which are arranged on a suction beam, contact the floor, and a fan device generates a suction flow which subjects a space between the first suction lip and the second suction lip to a negative pressure. 
     The invention also relates to a floor cleaning machine, comprising a suction beam on which a first suction lip and at least one second suction lip are arranged, and a fan device for generating a suction flow which subjects a space between the first suction lip and the second suction lip to a negative pressure. 
     A method for brush roller control of a vacuum cleaner floor nozzle is known from DE 41 37 886 A1. 
     A vacuum cleaner with an electric motor controlling a fan for generating an internal negative pressure and a flow of suction air is known from DE 694 09 462 T2. Means for controlling the speed of the electric motor are provided, which are designed for continuously controlling the speed of the electric motor as a function of the result of the measurement of a negative pressure and a differential pressure. 
     A device for automatic suction power control of a vacuum cleaner is known from DE 10 2008 010 068 A1. 
     A method for operating a vacuum cleaner with a suction fan driven by a fan motor and with a control device acting on the fan motor, the control device specifying as control variable the motor power or a parameter influencing the motor power, and in doing so taking into account the negative pressure generated by the suction fan, is known from EP 1 997 417 A2. The control device detects the negative pressure from the motor speed and a characteristic value correlating with the power of the fan motor. 
     A method of adjusting a vacuum level in a carpet cleaning machine is known from U.S. Pat. No. 6,176,940 B1. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a method is provided, with which an optimized vacuuming result is obtained. 
     In accordance with an embodiment of the invention, a negative pressure is detected, and the suction flow is adjusted such that the negative pressure lies at a set value or in a set value range, so that an angle of incidence of the first suction lip and the second suction lip on the floor lies at a set value or in a set value range. 
     The relative positioning of the suction lips in relation to the floor to be cleaned and, therefore, their angle of incidence depends upon the prevailing negative pressure. The negative pressure is determined, on the one hand, by the power of the fan device and, on the other hand, by the flow of ambient air into the space between the suction lips. The prevailing negative pressure is, in turn, dependent upon the floor structure conditions. For example, with the same power of the fan device, a higher negative pressure prevails with a smooth floor than with a rougher floor. The prevailing negative pressure may also depend upon the type of cleaning such as wet cleaning or dry vacuuming. 
     An optimized vacuuming result is obtained when the angle of incidence is not too steep and not too flat. For example, a set value for an angle of incidence is typically approximately 60°. It may, however, differ in accordance with the distance from the floor. 
     In the solution in accordance with the invention, the angle of incidence is adjusted to the set value or to the set value range by adjusting the negative pressure. This negative pressure is, in turn, adjusted by way of the fan device and, in particular, regulated so that the optimized vacuuming result is also obtained with varying floor structure conditions. 
     The method in accordance with the invention can be carried out, in particular, automatically. If, for example, during driving operation of the floor cleaning machine, the floor structure conditions change, an adjustment can then automatically take place in order to obtain an optimized vacuuming result. 
     It is, in particular, thereby achievable that the angle of incidence of the suction lips is at least almost constant also when the floor structure conditions change during driving operation. In one embodiment, the negative pressure is measured by one or more pressure sensors. 
     The negative pressure can thereby be directly detected, and, in particular, a set value control (regulation) carried out. 
     It is expedient for the negative pressure to be detected at the suction beam. It can thereby be measured in simple way. 
     It is quite particularly advantageous for the suction flow to be adjusted by adjusting the power of the fan device. The negative pressure can be adjusted to a set value or a set value range by corresponding activation of a motor of the fan device. (In principle, it is also possible to adjust the suction flow using corresponding flow elements such as flaps, etc.; simple adjustability is achieved by adjusting the power of the fan device.) 
     In particular, the suction flow is adjusted automatically, i. e., without user intervention. With optimized manageability of the floor cleaning machine, an optimized cleaning result is thereby obtained. 
     It is, in particular, advantageous for the negative pressure adjustment to be regulated with the regulation aim that the negative pressure detected lies at a set value or in a set value range. In particular, simple automatic adjustment is thereby achieved. 
     The regulation aim is (indirectly) a certain relative position of the suction lip in relation to the floor, i. e., a certain angle of incidence or a certain angle of incidence range, in order to obtain an optimized vacuuming result. 
     In particular, the set value or set value range for the angle of incidence of the first suction lip and the second suction lip on the floor lies in the range between 35° and 70° and, for example, at approximately 45° or approximately 60°. An optimized vacuuming result is then achieved. 
     It is expedient for the suction beam to be floatingly mounted on a chassis of the floor cleaning machine and, in particular, to be pressed against the floor. There is then no need to provide additional support by means of one or more wheels for the suction beam. A corresponding wheel can leave a streak on the floor to be cleaned. 
     It is expedient for the first suction lip and/or the second suction lip to comprise one or more cut-outs through which it is possible for ambient air to flow into the space between the first suction lip and the second suction lip. Optimized vacuuming is thereby achieved. 
     For example, the set value or set value range for the negative pressure and/or the angle of incidence is stored in a table or as function. In principle, the set value or set value range depends on the construction of the suction beam and also on the construction of a spring device by means of which the suction beam is floatingly mounted. 
     In accordance with the invention, a floor cleaning machine is provided, which can be operated with an optimized vacuuming result. 
     In accordance with an embodiment of the invention, a negative pressure detection device is provided, and a control device is provided, to which the negative pressure detection device is coupled with signaling effect, the control device controlling the subjection to negative pressure in dependence upon signals of the negative pressure detection device in such a way that a negative pressure lies at a set value or in a set value range, so that an angle of incidence of the first suction lip and the second suction lip on a floor to be cleaned lies at a set value or in a set value range. 
     The floor cleaning machine in accordance with the invention has the advantages explained hereinabove in conjunction with the method in accordance with the invention. 
     Advantageous configurations of the floor cleaning machine in accordance with the invention have been explained hereinabove in conjunction with the method in accordance with the invention. 
     In particular, the method in accordance with the invention can be carried out on the floor cleaning machine in accordance with the invention. 
     The control device is expediently coupled with signaling effect to the fan device and controls its power. A set value for the negative pressure, which is relevant for the angle of incidence of the suction lips, can thereby be adjusted in a simple way. 
     In particular, the negative pressure detection device comprises one or more pressure sensors. The corresponding negative pressure can thereby be directly detected. 
     It is then expedient for the pressure sensor or pressure sensors to be arranged on the suction beam. The corresponding negative pressure can thereby be detected in a simple way. 
     It is expedient for the suction beam to be floatingly mounted on a chassis of the floor cleaning machine. There is then no necessity for additional support by wheels. The suction beam can be pressed against the floor to be cleaned, so that the suction lips contact it. 
     In particular, a spring device is provided, which presses the suction beam against the floor to be cleaned. An optimized vacuuming result is thereby achievable. In an alternative embodiment, a spring device is provided, which provides a restoring force (away from the floor), with the suction beam being pressed by its own weight against the floor. Such a spring device provides stabilization, for example, when cornering. 
     In one embodiment, the first suction lip and/or the second suction lip comprises or comprise one or more cut-outs through which it is possible for ambient air to flow into the space between the first suction lip and the second suction lip. An effective vacuuming from the space between the first suction lip and the second suction lip is thereby achievable. The cut-outs may, for example, be configured as continuous openings on the first suction lip and/or the second suction lip. It is, for example, also possible for channels to be formed on the first suction lip and/or the second suction lip, which, when the corresponding suction lip is pressed with sufficient strength onto the floor to be cleaned, open a larger cross-sectional area in comparison with the case where the corresponding suction lip is not pressed onto the floor. 
     It is expedient for the floor cleaning machine to be self-propelled. This results in effective cleaning of large surfaces. By virtue of the solution in accordance with the invention, an optimized vacuuming result is also achieved with varying floor structure conditions. The floor cleaning machine may, for example, be designed as a ride-on machine or as a floor cleaning machine which is a “walk-behind” floor cleaning machine, which is guided by an operator. The floor cleaning machine may, for example, also be designed as a robot vacuum cleaner. It may, for example, also be designed as an apparatus without any prescribed direction of movement such as a hand-held apparatus. 
     The following description of preferred embodiments serves in conjunction with the drawings to explain the invention in greater detail. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic side view of an embodiment of a floor cleaning machine; 
         FIG. 2  shows a schematic representation of a suction beam with suction lips and coupling to a fan device; 
         FIG. 3( a )  shows a first example of a relative position of suction lips (angle of incidence) in relation to a floor to be cleaned in schematic representation; 
         FIG. 3( b )  shows a second example of an angle of incidence; 
         FIG. 3( c )  shows a third example of an angle of incidence; 
         FIG. 4  shows a front view of an embodiment of a suction beam with suction lips in the direction A in accordance with  FIG. 3( a ) ; and 
         FIG. 5  shows a schematic flow chart for controlling the relative position of suction lips in relation to the floor to be cleaned. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of a floor cleaning machine is a self-propelled floor cleaning machine which is shown schematically in  FIG. 1  and designated therein by  10 . The floor cleaning machine  10  comprises a chassis  12 . A front wheel  14  and a rear wheel assembly  16  are mounted on the chassis  12 . The floor cleaning machine can travel on a floor  18  to be cleaned by means of the front wheel  14  and the rear wheel assembly  16 . 
     In one embodiment, the front wheel  14  is connected to a steering device designated in its entirety by  20 . An angular position of the front wheel  14  in relation to a center plane of the floor cleaning machine  10  can be set by the steering device  20 . During straight-ahead travel (indicated by reference numeral  22  in  FIG. 1 ) the front wheel  14  is aligned parallel to this center plane and a corresponding steering angle is a zero angle. 
     Straight-ahead travel  22  includes forward travel  23  (cf. also  FIG. 3 ) and reverse travel. 
     The steering device  20  defines a steering axis  24 . The steering axis  24  preferably lies in the center plane. The steering axis  24  is oriented transversely and, for example, perpendicularly to a wheel axis  26  of the front wheel  14 . The front wheel  14  is rotatable about the wheel axis  26 . The wheel axis  26  extends transversely to the center plane. During straight-ahead travel  22  in the straight-ahead direction, the wheel axis  26  is oriented perpendicularly to the center plane. 
     Arranged on the chassis  12  is a seat  28  for a driver. A driver seated on the seat  28  can operate a steering wheel  30  of the steering device  20 . 
     In one embodiment, the floor cleaning machine  10  comprises an accelerator pedal  32  and a brake pedal as actuating elements. By actuation (in particular, actuation by foot) of this accelerator pedal  32 , an operator specifies the speed of the floor cleaning machine  10 . A drive for the front wheel  14  and/or the rear wheel assembly  16  is provided for this. 
     The rear wheel assembly  16  comprises (at least) one left rear wheel and (at least) one right rear wheel. Here the designation “left” and “right” relates to the direction of forward travel in straight-ahead travel  22 . 
     The left rear wheel and the right rear wheel  34  are rotatable about a common wheel axis  36 . The wheel axis  36  is fixed in relation to the center plane and perpendicular thereto; in particular, the rear wheel assembly  16  is unsteered. 
     In the embodiment shown, the floor cleaning machine  10  is three-wheeled. 
     The floor cleaning machine  10  is constructed as a scrubber-suction machine. It comprises a floor cleaning appliance  38  which, in the embodiment shown, is a scrubber floor cleaning appliance. The scrubber floor cleaning appliance has scrubbing elements  40  arranged on an underside  42  of the chassis  12 . A scrubbing element  40  is arranged between the rear wheel assembly  16  and the front wheel  14 , for example, rotatably so as to face the floor  18  on which the floor cleaning machine  10  stands. 
     The floor cleaning appliance  38  further comprises an application device  44  for cleaning liquid, with which cleaning liquid can be applied to an application area on the floor  18  to be cleaned. The cleaning liquid is, for example, a mixture of water and a chemical cleaning additive. The application device  44  comprises a plurality of nozzles through which the cleaning liquid can be applied to the application area. The nozzles may be arranged in one or more rows. 
     The nozzles are so arranged and constructed that the scrubbing element or scrubbing elements  40 , which are cleaning tools, are directly sprayed or cleaning liquid gets from there onto the floor  18  and/or that the floor  18  is sprayed. 
     The application area for cleaning liquid lies between the front wheel  14  and the rear wheel assembly  16 . 
     A tank for cleaning liquid is arranged on the chassis  12 . The tank may include an area for, for example, water and an area for chemical additives. The nozzles are supplied with cleaning liquid by way of the tank or by way of a mixing area. 
     The floor cleaning machine  10  comprises a suction device  46  by means of which liquid can be sucked up from the floor  18 . The suction device  46  comprises a suction beam  48  on which (at least) a first suction lip  50  and a second suction lip  52  ( FIGS. 2, 3 ( a ),  3 ( b ),  3 ( c ),  4 ) are arranged. 
     In the embodiment shown, the suction beam  48  is arranged, in relation to a forward direction of travel, behind the rear wheel assembly  16 . The second suction lip  52  lies closer to the rear wheel assembly  16  than the first suction lip  50 . Liquid is sucked in by way of the suction beam  48  and collected in a dirty water tank  53  ( FIG. 2 ). 
     In an alternative embodiment, a suction beam corresponding to the suction beam  48  is arranged in front of the rear wheel assembly  16 . The suction beam may also be arranged directly on the floor cleaning appliance  38 . The suction beam may also be directly integrated in the floor cleaning appliance. 
     It is, for example, also possible for a suction beam to be arranged in front of the floor cleaning appliance  38  (between the floor cleaning appliance  38  and the front wheel  14 ) or behind the floor cleaning appliance  38  (between the rear wheel assembly  16  and the floor cleaning appliance  38 ). 
     A fan device  54  ( FIG. 2 ) is arranged on the chassis  12 . The fan device  54  is driven by a motor  56  which, in particular, is an electric motor. The fan device  54  is fluidically connected to the suction beam  48  by a pipe device  58 . 
     When the floor cleaning machine  10  is in cleaning operation, the first suction lip  50  and the second suction lip  52  contact the floor  18 . A space  60  is formed between the first suction lip  50  and the second suction lip  52 . The space  60  is closed at the sides, for example, by a corresponding formation of the first suction lip  50  and/or the second suction lip  52 , in which the suction lips  50 ,  52  contact each other. 
     In an alternative embodiment, the space  60  is not completely closed, but partially closed. 
     The suction beam  48  has one or more vacuuming openings  62 . The vacuuming opening  62  or the vacuuming openings  62  has or have a mouth  64  opening into the space  60 . The vacuuming opening  62  or the vacuuming openings  62  is or are also connected to the pipe device  58 . 
     The fan device  54  generates a suction flow (indicated by reference numeral  66  in  FIG. 2 ). This suction flow  66  causes the space  60  to be subjected to negative pressure in order to suck in, in particular, excess liquid. 
     The first suction lip  50  and/or the second suction lip  52  are each provided with cut-outs  72  through which ambient air (indicated by the arrow with reference numeral  74  in  FIG. 2 ) can flow into the space  60 . In particular, only the second suction lip  52  is provided with cut-outs  72 . 
     In one embodiment, cut-outs  72 , starting from a bottom edge  76 , are arranged on the first suction lip  50  and the second suction lip  52 . 
     The suction beam  48  is floatingly arranged on the chassis  12 . In particular, it is held by a spring device  78  on the chassis  12 . The spring device  78 , comprising, in particular, one or more springs, serves, for example, for stabilization when cornering and for provision of a restoring force away from the floor  18 . 
     For example, the suction beam  48  is pressed by its own weight in the direction of the floor  18 . The first suction lip  50  and the second suction lip  52  are pressed onto the floor  18  and contact it. During operation, the negative pressure that is created acts additionally and the differential pressure subjects the suction beam  48  to load corresponding to the adjustment of the suction lips  50  and  52  to the floor  18 . 
     In an alternative embodiment, the spring device  78  comprises pressure springs which press the suction beam against the floor to be cleaned. 
     The floor cleaning machine  10  comprises a control device  80 . The control device  80  is coupled with signaling effect to the fan device  54  with the motor  56 . 
     The control device  80  controls (in an open loop or closed loop) the power of the fan device  54  and, consequently, the suction flow  66 . 
     The floor cleaning machine  10  comprises a negative pressure detection device  82 . The negative pressure detection device  82  detects at an appropriate place a negative pressure in the course of a suction flow. 
     In one embodiment, the negative pressure detection device  82  comprises a pressure sensor  84  (or a plurality of pressure sensors  84 ). This pressure sensor  84  is arranged on the suction beam  48 . For example, it is arranged in the vacuuming opening  62 . 
     The negative pressure detection device  82  (and, in particular, the pressure sensor  84 ) is coupled with signaling effect to the control device  80 . It passes its detection signals on to the control device  80 . 
     During suction operation of the floor cleaning machine  10 , the spring device  78  first presses with a predetermined force the suction beam  48  in the direction of the floor  18  and, therefore, presses the first suction lip  50  and the second suction lip  52  against the floor  18 . The fan device  54  generates the suction flow  66 . The negative pressure prevailing at the suction beam  48  determines the relative position of the first suction lip  50  and the second suction lip  52  in relation to the floor  18 . 
     The prevailing negative pressure is, in turn, determined by the power specification of the fan device  54  and by the flow-in relations of ambient air  74  into the space  60 . These flow-in relations are, in principle, dependent upon the type of floor  18 . They may differ, depending on whether the floor  18  is smooth or rough. 
     An optimized vacuuming result is achieved when an angle of incidence  86  ( FIG. 3( b ) ) for the first suction lip  50  and the second suction lip  52  lies at a certain set value or in a certain set value range. The angle of incidence  86  is that angle which lies between the corresponding suction lip  50  or  52  and the floor  18  at the point at which the suction lip contacts the floor  18 . 
     It has proven advantageous for the angle of incidence  86  to be approximately 45° and, for example, to lie in a range between 35° and 55°. 
     An angle of incidence  86  of approximately 90° is shown in  FIG. 3( a ) . An angle of incidence of approximately 0° is shown in  FIG. 3( c ) . 
     The angle of incidence  86  is specified by the power of the fan device  54 . However, with the same power specification, the angle of incidence  86  with the same suction beam  48  may differ with different floors  18 . The relative position of the first suction lip  50  and the second suction lip  52 , shown in  FIG. 3( b ) , with an angle of incidence  86  in the aforementioned set value range is optimal for the vacuuming result. 
     The negative pressure detected by the negative pressure detection device  82  is a measure for the relative position of the first suction lip  50  and the second suction lip  52  in relation to the floor  18 , i. e., for the angle of incidence  86 . 
     In the solution in accordance with the invention, the negative pressure, in particular, in the vacuuming opening  62  is adjusted to a set value by way of corresponding power setting of the fan device  54 , in order to obtain an optimized angle of incidence  86  as independently as possible of the structure of the floor  18 . 
     The control device  80  receives by way of the negative pressure detection device  82  corresponding detection results and, in particular, measurement results of the pressure sensor or pressure sensors  84  for the prevailing negative pressure. If there is a deviation from a set value or a set value range for the negative pressure, the power of the fan device  54  is varied accordingly by activating the motor  56 , in order to bring the negative pressure to a set value and thereby set the optimized angle of incidence  86 . 
     The adjustment occurs, in particular, automatically so that without any intervention by a driver, as it were, the floor cleaning machine  10  recognizes a variation in the structure of the floor and independently carries out an adjustment in the power setting of the fan device  54 , in order to also obtain an optimized vacuuming result in the event of a variation in the structure of the floor. 
     In particular, a regulation method (control method) is carried out, with a regulation aim of setting a negative pressure set value, in particular, in the vacuuming opening  62  and, therefore, setting a set value for the angle of incidence  86 . The variable factor (control parameter) is the power of the fan device  54 , the variation being carried out by the control device  80  activating the motor  56  accordingly. 
     In one embodiment, the regulation is carried out (cf.  FIG. 5 ) by a testing  88  of the negative pressure (detected by way of the negative pressure detection device  82 ). If the testing  88  shows that the negative pressure detected lies below the set value (indicated by reference numeral  90  in  FIG. 5 ), the power of the fan device  54  is then increased. This is indicated by reference numeral  92  in  FIG. 5 . 
     If a further testing shows that the set value is reached (indicated by reference numeral  94  in  FIG. 5 ), an optimized vacuuming result is achieved, which is indicated by reference numeral  96  in  FIG. 5 . An optimized vacuuming result means that the angle of incidence  86  lies at its set value or in its set value range. 
     If the testing  88  shows that the negative pressure in the vacuuming opening  62  lies above the set value (indicated by reference numeral  98  in  FIG. 5 ), the power of the fan device  54  is then reduced. This is indicated by reference numeral  100  in  FIG. 5 . 
     If a further testing shows that the set value is reached (method step  94 ), the optimized vacuuming result  96  is then achieved. 
     Should the set value not be reached after steps  92  or  100 , as is indicated by reference numeral  102  in  FIG. 5 , this means that a problem has arisen which cannot be solved by the corresponding regulation method. Such a problem is, for example, excessive wear of a suction lip  50  or  52 , clogging of the vacuuming opening  62  and/or of the pipe device  58 , etc. This requires user intervention. A corresponding warning is then issued to the operator. This is indicated by reference numeral  104  in  FIG. 5 . 
     After corresponding user intervention (indicated by reference numeral  106  in  FIG. 5 ), the set value should then be reached and step  94  achieved. User intervention is, in particular, checking the floor cleaning machine  10  or cleaning the floor cleaning machine  10  or replacing a suction lip. 
     During driving operation of the floor cleaning machine  10 , in particular, the testing  88  is done permanently and, for example, at specified time intervals. The floor cleaning machine  10  can thus independently and automatically make an adjustment to varying floor structure conditions, in order to also obtain an optimized vacuuming result under different floor structure conditions. In particular, controlling is carried out such that at least approximately the first suction lip  50  and the second suction lip  52  lie at the optimized angle of incidence  86  or in an optimized angle of incidence range (set value or set value range) relative to the floor  18  independently of the floor structure conditions. 
     Generally, lower power is required for the fan device  54  with smoother floors in comparison with rough floors. 
     In the solution in accordance with the invention, the power of the fan device  54  is automatically adjusted during drive-suction operation of the floor cleaning machine  10 , in order to obtain an optimized vacuuming result. 
     The power of the fan device  54  is controlled in accordance with the negative pressure data provided by the negative pressure detection device  82 . The negative pressure prevailing at the suction beam  48  is a measure for the angle of incidence  86  of the suction lips  50  and  52 . 
     In principle, the set value of the negative pressure or the corresponding set value range depends on the construction of the suction beam  48  in combination with the construction of the spring device  78 . For example, the corresponding set value or set value range is stored in the control device in dependence upon the construction of the suction beam  48  and the spring device  78  in a table or as function. 
     It is, in principle, possible for the negative pressure to also be detected at points other than at the suction beam  48  by the negative pressure detection device  82 . Additional warning and evaluating possibilities exist as a result of detection of the negative pressure data by the negative pressure detection device  82 . For example, a warning can be issued to an operator if the negative pressure required for cleaning purposes cannot be generated. 
     Furthermore, a warning or information about wear of the suction lips  50 ,  52  can be displayed. For example, a corresponding calculation rule is stored for this purpose in the control device  80 . 
     Information or a warning that, for example, a tank lid does not close properly can also be issued. 
     Further ways of using the negative pressure data obtained are also possible. 
     The method in accordance with the invention can also be used on other types of floor cleaning machines. For example, it can be used on a robot vacuum cleaner or on floor cleaning machines with articulated steering. It is used, in particular, on self-propelled floor cleaning machines. 
     
       
         
           
               
             
               
                   
               
               
                 List of Reference Numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 10 
                 floor cleaning machine 
               
               
                 12 
                 chassis 
               
               
                 14 
                 front wheel 
               
               
                 16 
                 rear wheel assembly 
               
               
                 18 
                 floor 
               
               
                 20 
                 steering device 
               
               
                 22 
                 straight-ahead travel 
               
               
                 23 
                 forward travel 
               
               
                 24 
                 steering axis 
               
               
                 26 
                 wheel axis 
               
               
                 28 
                 seat 
               
               
                 30 
                 steering wheel 
               
               
                 32 
                 accelerator pedal 
               
               
                 34 
                 right rear wheel 
               
               
                 36 
                 wheel axis 
               
               
                 38 
                 floor cleaning appliance 
               
               
                 40 
                 scrubbing element 
               
               
                 42 
                 underside 
               
               
                 44 
                 application device 
               
               
                 46 
                 suction device 
               
               
                 48 
                 suction beam 
               
               
                 50 
                 first suction lip 
               
               
                 52 
                 second suction lip 
               
               
                 53 
                 dirty water tank 
               
               
                 54 
                 fan device 
               
               
                 56 
                 motor 
               
               
                 58 
                 pipe device 
               
               
                 60 
                 space 
               
               
                 62 
                 vacuuming opening 
               
               
                 64 
                 mouth 
               
               
                 66 
                 suction flow 
               
               
                 72 
                 cut-out 
               
               
                 74 
                 ambient air 
               
               
                 76 
                 bottom edge 
               
               
                 78 
                 spring device 
               
               
                 80 
                 control device 
               
               
                 82 
                 negative pressure detection device 
               
               
                 84 
                 pressure sensor 
               
               
                 86 
                 angle of incidence 
               
               
                 88 
                 testing 
               
               
                 90 
                 “below set value” 
               
               
                 92 
                 “increase power” 
               
               
                 94 
                 “set value reached” 
               
               
                 96 
                 “optimized vacuuming result” 
               
               
                 98 
                 “above set value” 
               
               
                 100 
                 “reduce power” 
               
               
                 102 
                 “set value not reached” 
               
               
                 104 
                 “warning” 
               
               
                 106 
                 “user intervention”