Abstract:
A floor cleaning machine having a speed control and steering member which operates under operator-applied deformation thereof. The invention provides improved consumer convenience at steering and/or speed control.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to floor cleaning machines and in particular to automatic floor cleaning and treating machines which are used for the cleaning of carpets and hard surfaces of large floor areas, such as in hotels, factories, office buildings, shopping centers and the like. 
         [0002]    In general such machines comprise a movable body carrying a brushing means, reservoirs for storing fresh and spent cleaning liquid, means for dosing fresh cleaning liquid onto the floor and a squeegee/vacuum pick-up system for recovering spent cleaning liquid from the floor. 
         [0003]    These machines are normally power-operated comprising a pair of driving wheels for moving the body, a motor for driving the wheels, and steering and speed control members for operating the driving motor. Steering may either be manual or by way of differentiated control of the individual wheel speeds. 
         [0004]    The present invention now in particular relates to a means for controlling speed and/or steering of a floor cleaning machine. 
       SUMMARY OF THE INVENTION 
       [0005]    According to some embodiments of the invention there is provided a floor cleaning machine comprising a body, a pair of driving wheels for moving the body, an electric motor is coupled to each driving wheel, and a steering assembly for controlling the operation of the driving motors and the direction of motion of the floor cleaning machine. The steering assembly includes a member that is deformable under operator-applied force and also comprises a component which is capable of controlling the current provided to each driving motor as a function of operator-applied deformation of the member. 
         [0006]    One particular embodiment of the present invention is directed toward a steering assembly for a floor cleaning machine having a pair of drive wheels powered by independent motors. The steering assembly includes an elongated frame member and a hand manipulable pivotal member coupled to the frame member. The hand manipulable pivotal member is pivotable about an axis normal to the elongated frame member. A spring extends between the frame member and the hand manipulable pivot member. The spring is positioned and configured to exert a force on the frame member in response to pivotal movement of the hand manipulable pivotal member. A sensor is coupled to the elongated frame member to detect deformation of the frame member due to exerted forces by the spring. A control is coupled to the sensor and the motors of the drive wheels of the cleaning machine. The control receives signals from the sensor and selectively powers each drive wheel motor in response to the signals from the sensor. 
         [0007]    Another embodiment is directed toward a steering assembly for a floor cleaning machine having a pair of drive wheels powered by independent motors. The steering assembly comprises a frame member and a handle bar coupled to the frame member and positioned substantially normal to the frame member. The handle bar has cantilevered ends relative to the frame member, wherein an applied force to the cantilevered ends of the handle bar cause the frame member to deform. A sensor is coupled to the frame member to detect deformation of the frame member due to exerted force on the cantilevered ends of the handle bar. A controller is coupled to the sensor and the motors of the drive wheels of the cleaning machine. The controller receives signals from the sensor and selectively powers each drive wheel motor in response to the signals from the sensor. 
         [0008]    Another embodiment is directed toward a steering and speed control assembly of a floor cleaning machine. The steering and speed control assembly comprises a frame member having a hand manipulable speed control device and a hand manipulable pivotal steering control member coupled to the frame member. The hand manipulable pivotal steering control member is pivotable about an axis normal to the frame member. A spring extends between the frame member and the hand manipulable pivotal steering control member. The spring is positioned and configured to exert a force on the frame member in response to pivotal movement of the hand manipulable pivotal steering control member. A sensor is coupled to the frame member to detect deformation of the frame member due to exerted forces by the spring. A controller is coupled to the sensor, the hand manipulable speed control device, and the motors of the drive wheels of the cleaning machine. The controller receives signals from the sensor and selectively powers each drive wheel motor in response to the signals from the sensor. The controller also receives signals from the hand manipulable speed control device and powers both drive wheel motors in response to the signals from the hand manipulable speed control device. In some embodiments, the speed control device is directly coupled to the hand manipulable pivotal steering control member. 
         [0009]    Another embodiment is directed toward a steering and speed control assembly of a floor cleaning machine. The steering and speed control assembly comprises a frame member having a hand manipulable speed control device and a handle bar steering control member coupled to the frame member. The handle bar has cantilevered ends relative to the frame member, wherein an applied force to the cantilevered ends of the handle bar cause the frame member to deform. A sensor is coupled to the frame member to detect deformation of the frame member due to exerted force on the cantilevered ends of the handle bar. A controller is coupled to the sensor and the motors of the drive wheels of the cleaning machine. The controller receives signals from the sensor and selectively powers each drive wheel motor in response to the signals from the sensor. The controller also receives signals from the hand manipulable speed control device and powers both drive wheel motors in response to the signals from the hand manipulable speed control device. In some embodiments, the speed control device is directly coupled to the handle bar steering control member. 
         [0010]    Further aspects of the present invention, together with the organization and operation thereof, will become apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a floor cleaning machine with a steering assembly embodying aspects of the present invention. 
           [0012]      FIG. 2  is a perspective view of a steering assembly embodying aspects of the present invention. 
           [0013]      FIG. 3  is another perspective view of the steering assembly shown in  FIG. 2 , with the steering device rotated relative to  FIG. 2 . 
           [0014]      FIG. 4  is a schematic view of the steering assembly illustrated in  FIG. 2 , shown in relation to the sensor, controller, and drive wheel motors. 
           [0015]      FIG. 5  is a schematic view of an alternative steering assembly embodying aspects of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected,” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Finally, as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention. Accordingly, other alternative mechanical configurations are possible, and fall within the spirit and scope of the present invention. 
         [0017]    Referring now to  FIG. 1 , a floor cleaning machine  10  is shown, comprising a housing  11 , an operator control assembly  12 , a scrubbing assembly  13  and a squeegee  14 . The cleaning machine  10  is supported on main drive wheels  16 ,  17  and one or more caster wheels  18 . Although it is not illustrated, several items such as a tank, batteries, pumps, motors, and other parts can be housed within the housing  11 . 
         [0018]    Although the invention will be described in connection with a scrubber, it should be clear that the control has application to other types of vehicles that are controlled by an operator walking or riding behind the machine and are propelled by two electric motors, such as battery powered sweepers and the like. Accordingly, the present invention should not be limited to a scrubber. 
         [0019]    As shown in  FIG. 1 , an operator control assembly  12  which is positioned toward the rear of the machine and used by the operator to control speed and direction. The operator control assembly includes a steering assembly  20  and speed control lever  22 . Accordingly, speed and direction can be controlled independently with this operator control assembly  12 . Although the speed control lever  22  is not directly coupled to the steering assembly  20 , in some embodiments, the speed control device  22  can be directly coupled to or integrated into the steering assembly  20 . For example, in some embodiments, the speed control device  20  can be integrated into or manipulated by a rotatable hand grip. Under such an alternative configuration, the speed control device  22  can still remain independently controlled. 
         [0020]    As shown in  FIGS. 2 and 3  and schematically illustrated in  FIG. 4 , the steering assembly  20  includes a hand manipulatable pivotal member or handle bar  24  having hand grips  26 . The pivotal member  24  is pivotally coupled to and supported on a bar or frame member  28 . As illustrated, the pivotal member  24  is positioned on the frame member  28  to rotate about an axis that is substantially normal to the frame member  28 . 
         [0021]    A spring  30  extends between the pivotal member  24  and the frame member  28 . The spring can be a torsion spring, or more specifically, a dual throw coil spring. However, in other embodiments, other types of bias elements can be used. The spring  30  biases the pivotal member to a neutral position, such as the position illustrated in  FIG. 2 . The spring  30  generates a force on the frame member  28  in response to the pivotal member  24  being rotated from the neutral position, such as shown in  FIG. 4 . This force causes deformation or bending of the frame member  28 . As described below, this deformation is measured and used to steer the floor cleaning machine  10 . 
         [0022]    An alternative embodiment of the steering assembly  20  is shown schematically in  FIG. 5 . Unlike the embodiment shown in  FIG. 4 , the handle bar  24  of this embodiment is rigidly fixed to the frame member  28 . In other words, the handle bar  24  does not pivot with respect to the frame member  28 . Accordingly, any attempt to steer the floor cleaning machine  10  via the handle bar  24  will directly cause the frame member to bend or deform. Like the previous embodiment, this deformation is then measured and used to steer the floor cleaning machine. 
         [0023]    In both embodiments, a sensor  32  is coupled to the frame member  28  to measure the deformation of the frame member  28 . Many different sensors can be used to measure the deflection, deformation, or amount of bending in the frame member  28 . For example, strain gauges, a Hall-effect sensors, and other deformation sensitive components can be used to measure the deformation. This measurement can then be used to cause the floor cleaning machine to turn a desired amount as described below. 
         [0024]    As schematically illustrated in  FIGS. 4 and 5 , a separate drive motor  34 ,  35  is coupled to each drive wheel  16 ,  17 . As such, each wheel can be driven independently to cause the floor cleaning machine  10  to turn. The drive motors  34 ,  35  are controlled in part by the sensor  32 . In general, the deformation-sensitive component or sensor  32  does not necessarily directly control the current of the driving motors, but preferably is coupled to a controller, amplifying circuit, or other components  33  that control the motor current or power based at least partially upon the information received from the sensor  32 . 
         [0025]    In operation, the floor cleaning machine  10  can be placed in motion by manipulating the speed control lever  22 . The direction can be independently controlled via the steering assembly  20 . As illustrated in embodiment shown in  FIG. 4 , the pivotal member  24  can be pivoted with respect to the frame member  28  by applying a force to the hand grips  26 . By pivoting the pivotal member  24 , the spring  30  places a force on the frame member  28 , causing the frame member  28  to deform or bend. The sensor  32  measures the deformation of the frame member  28  and relays the measurement to a controller  33 , which then controls the power provided to each drive motor  34 ,  35 . For example, in the illustrated embodiment of  FIG. 4 , the steering assembly is rotated to cause a left turn. As such, the power to the left motor  34  may be decreased, while the power to the right motor  35  remains the same or is increased. 
         [0026]    Once the pivotal member  24  of  FIG. 4  is released, the spring  30  returns the pivotal member  24  to the neutral position. As such, the bending or deforming force is removed from the frame member  28  and the frame member  28  elastically returns to a non-deformed configuration. Accordingly, no deflection will be detected by the sensor and equal power will be provided to each drive wheel motor  34 ,  35 . 
         [0027]    The operation of the embodiment shown in  FIG. 5  is similar to the operation of the embodiment shown in  FIG. 4 , except the handle bar  24  assembly does not pivot with respect to the frame member. Rather, a force applied to the handle bar  24  directly causes deformation of the frame member  28 . The sensor  32  measures the deformation of the frame member  28  and relays the measurement to a controller  33 , which then controls the power provided to each drive motor  34 ,  35 . 
         [0028]    Once the force applied to handle bar  24  of  FIG. 5  is released, the elastic force of the frame member  28  causes the frame member  28  to elastically return to a non-deformed configuration. Accordingly, no deflection will be detected by the sensor and equal power will be provided to each drive wheel motor  34 ,  35 . 
         [0029]    The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention. For example, various alternatives to the certain features and elements of the present invention are described with reference to specific embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular embodiment are applicable to the other embodiments. 
         [0030]    Various features of the invention are set forth in the following claims.