Abstract:
A floor cleaning device employing a brush assembly is provided. The brush assembly includes a front brush and a rear brush that spin about an axis line generally parallel to the surface being cleaned. The spinning rotation of the brush along with the configuration of the housing help provide an airflow path that sucks debris from the surface being cleaned. The debris is directed to a hopper wherein larger items are captured and smaller items are suctioned into a vacuum bag.

Description:
[0001]    This application is related to U.S. Pat. Nos. 5,555,596, entitled “Floor Cleaning Apparatus”; 5,485,653, entitled “Floor Cleaning Apparatus”; 5,628,086, entitled “Floor Cleaning Apparatus with Squeegee Mounting System”; and 5,608,947, entitled “Floor Cleaning Apparatus With Pre-Filter”; the entire disclosures of which are incorporated by reference herein. This application is also related to U.S. patent application Ser. No. 11/059,663, filed Feb. 15, 2005, now U.S. Pat. No. 7,533,435, which is a Continuation-In-Part of U.S. patent application Ser. No. 10/737,027, filed Dec. 15, 2003, now abandoned, which is a Continuation-In-Part of U.S. patent application Ser. No. 10/438,485, filed May 14, 2003, now abandoned, the entire disclosures of which are incorporated by reference in their entirety herein. This application is also related to U.S. Patent Application Publication Nos. 2009/0094784, 2006/0064844, 2006/0124770, and 2006/0156498, and U.S. patent application Ser. No. 12/511,704, filed Jul. 29, 2009, the entire disclosures of which are incorporated by reference herein. One of skill in the art will appreciate that the aspects described in these references may be combined with the aspects of embodiments of the present invention described herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention generally relate to floor cleaning apparatus that employ a sweeper and scrubber assembly that possesses a vacuum&#39;s ability to capture small particles and/or debris and that produces a lower noise output than typical sweeper/brush apparatus. 
       BACKGROUND OF THE INVENTION 
       [0003]    Floor cleaning apparatus are generally comprised of a chassis supported by a plurality of wheels, one of which is steerable to control the path of the machine. The chassis also accommodates a cleaning assembly, such as a brush, a sweeper, a squeegee, a burnisher, etc. The chassis also supports tanks used to hold water, cleaning fluids, and spent cleaning fluids suctioned from the surface being cleaned. Floor cleaning apparatus also often possess a receptacle or bag for holding collected dust and debris. The majority of the components associated with the cleaning machine are surrounded by at least one housing that protects the internal components from the environment and prevents individuals that are working around the machine from touching the often hot internal components. As floor cleaning apparatus are sometimes used in tight spaces, such as bathrooms and hallways, it is often desirable to make floor cleaning apparatus as compact as possible. 
         [0004]    Some floor cleaning apparatus employ a rotating sweeper broom (“sweeper”) to lift debris from a floor. Generally, a cylindrical sweeper rotates about an axis that is parallel to the floor and which may be located between front and rear wheels of the apparatus. Floor cleaning apparatus also typically include a vacuum system that establishes a directional airstream adjacent to the broom to direct debris into a hopper where heavier debris is precipitated from the airstream. Lighter debris, especially dust, is then typically directed to a vacuum bag. 
         [0005]    To enhance the suctioning effect provided by the vacuum, the sweeper may be located in a housing situated between the front and rear wheels. The housing typically includes one or more flaps or seals that surround the sweeper that defines a skirt with a lower edge that contacts the floor. The flaps or seals are generally flexible or hinged to the chassis to allow debris to enter the assembly and be swept up by the sweeper. The flaps or seals also prevent the sweeper from throwing debris and dust as it rotates. 
         [0006]    Some floor cleaning apparatus treat the floor with a cleaning solution with at least one scrubber brush. In some apparatus, the cleaning solution is deposited onto the floor and a pair of rotating disk brushes are used to scrub the floor. Wastewater, which includes entrained debris, is then typically suctioned by a vacuum squeegee that is located behind or adjacent to the brushes. 
         [0007]    One example of a floor cleaning apparatus is disclosed in U.S. Pat. No. 5,093,955 to Blehert et al. (“Blehert I”) entitled “Combined Sweeper and Scrubber.” Blehert I discloses a floor cleaning apparatus that can be set either to a sweeper mode or a scrubbing mode. Blehert I provides a single cylindrical rotary brush, a brush housing mounted on a frame, a solution tank and a removable debris hopper. When in the sweeping mode, a vacuum operating in conjunction with an air circuit draws air from around the brush and through a filter. When in a scrubbing mode, the vacuum operates to recover dirty scrubbing solution from the rear of the apparatus through a squeegee located aft of the brush. 
         [0008]    U.S. Pat. No. 6,041,471 to Charky et al. (“Charky”) entitled “Mobile Walk-Behind Sweeper” discloses a mobile sweeper for cleaning dust and collecting garbage from surfaces. Charky employs a plurality of brushes that direct dust to a collection point where a vacuum blower suctions the debris into a collection container. 
         [0009]    U.S. Pat. No. 4,819,676 to Blehert et al. (“Blehert II”) entitled “Combination Sweeping and Scrubbing System and Method,” discloses an apparatus that comprises a sweeping assembly that can be converted into a scrubbing unit and vice versa. The sweeping assembly includes a removable hopper. Cylindrical brushes are also provided that operate in either the sweeping or scrubbing mode. 
         [0010]    U.S. Pat. No. 4,580,313 to Blehert (“Blehert III”) entitled “Walk Behind Floor Maintenance Machine” discloses a floor treatment apparatus that has a plurality of wheels, a removal hopper, and a rotatable brush. A removable filter housing is also contemplated and has a prismatic shape. The design of the filter housing is such that a means for vibrating the filter is needed to dislodge particles. Additionally, the cylindrical brushes of Blehert III are not enclosed within the housing. 
         [0011]    None of the references discussed above disclose a floor cleaning apparatus with a housing that serves to encase an entire cleaning assembly; 2) a hopper with a taper that allows debris separation; 3) a seal created by a flap located around the cleaning assembly; 4) placement of the cleaning assembly near the front of the device that facilitates air flow; and 5) a retractable vacuum hose. Further, the prior art apparatus are noisy and do not provide a sufficient vacuum. Another drawback is that the prior art apparatus will capture large debris that can potentially cause clogs and damage to internal vacuum components. 
         [0012]    Thus it is a long felt need to provide a floor cleaning apparatus that employs a sweeper and scrubber assembly that collects debris of many sizes that is relatively quiet compared to apparatus of the prior art. 
       SUMMARY OF THE INVENTION 
       [0013]    It is one aspect of the present invention to provide a floor cleaning apparatus (“apparatus”) that employs a scrubber and sweeper assembly (hereinafter “cleaning assembly”). The cleaning assembly includes a front brush and a rear brush that are partially enclosed by a housing that, with the aid of a vacuum motor, directs air between the front brush and the second brush and into a hopper. The suction provided by the vacuum motor directs particle- and debris-laden air into the hopper wherein smaller particles are suctioned directly into a vacuum bag. The vacuum pressure provided by the vacuum motor is maintained by a seal or flap that is associated with the undercarriage of the apparatus. The hopper of one embodiment of the present invention also includes a screen that captures larger particles while allowing dust and smaller particles to pass therethrough to be suctioned into the vacuum bag. The hopper is removable, which allows the user to clear the larger particles from the apparatus. 
         [0014]    It is, thus, another aspect of the present invention to provide an apparatus that is capable of cleaning small particles and large particles. More specifically, the front brush and the rear brush are located under the brush housing. The rear brush is also located near a curved rear wall of the hopper. This configuration allows air and debris to enter the front portion of the cleaning assembly, flow between the rotating brushes, flow behind the curved wall, and flow into the hopper. As one skilled in the art will appreciate, this configuration thus allows for the capture of particles of various sizes, from the very small, i.e., dust, to larger particles of about 0.75 inches. Additionally, larger particles of 8 to 10 inches of length may be captured by some embodiments of the present invention. In one embodiment of the present invention, the brushes are cylindrical and rotate about a longitudinal axis that is parallel to the floor. As mentioned above, a flap or seals may be positioned about the brushes to seal the housing, which enhances suction pressure and facilitates the airflow described above. The flaps may be made of any material, but are preferably made of a compliant material, such as rubber. In one embodiment of the present invention, the rearward flap also functions as a squeegee. 
         [0015]    It is another aspect of the present invention to provide a debris tray that also employs a screen that captures larger items. More specifically, the removable debris tray of the hopper of one embodiment of the present invention is tapered wherein a lowermost portion thereof is associated with a vacuum hose that is associated with the vacuum bag. The hopper also includes a screen that is positioned above the debris tray such that debris-laden air passes through the screen and into the tray, where larger debris will be trapped by the screen and prevented from entering the vacuum hose. As is well known in the art, the smaller debris will be deposited into the vacuum bag. The debris tray is removable, which allows the larger particles to be cleared from the cleaning assembly periodically. The screen prevents jamming of the vacuum hose, which is an advantage over prior art apparatus that did not capture larger debris or that captured larger debris only to inadvertently suck them into the vacuum system, which could damage the vacuum hose, vacuum motor or other components of the system. 
         [0016]    It is yet another aspect of the present invention to provide an apparatus that has a retractable attachment hose. More specifically, one embodiment of the present invention includes an auxiliary vacuum hose that is interconnected to the vacuum bag by way of a valve. In normal operations, vacuum pressure provided by the vacuum motor suctions debris pulled by the cleaning apparatus. Alternatively, when the attachment hose is employed, the valve closes the vacuum hose associated with the cleaning apparatus and provides vacuum pressure to the attachment hose. The attachment hose may be associated with a hose roller that maintains the curvature of the hose to prevent kinking and the associated airflow reduction. Furthermore, some embodiments of the present invention provide a hose with bellows or other elongation mechanisms. In one embodiment of the present invention, the hose roller is actuated when the operator switches the apparatus to the primary floor cleaning mode. 
         [0017]    It is another aspect of the present invention to provide a cleaning device associated which is suspended beneath the main body of the cleaning apparatus. More specifically, embodiments of the present invention provide a spring or other biasing mechanism, which is associated with the main housing of the apparatus on one end and an armature associated with the cleaning device on the other end, that supports the weight of the cleaning device while allowing it to move efficiently along the floor. The spring length and tension may be selectively altered to adjust the amount of “float” the cleaning devices possesses and/or to otherwise tune the functionality of the overall device. Preferably, the selection of spring stiffness is preset by the apparatus designer such that optimum or near optimum performance is achieved regardless of the surface being cleaned For example, if a stiff or short spring is employed, most of the cleaning assembly&#39;s weight will cycle from floor to spring, which affects brush contact, brush performance, etc. 
         [0018]    It is still yet another aspect of the present invention to provide an apparatus having a unique vacuum bag. More specifically, embodiments of the present invention employ a vacuum bag with a centering tab and an automatic seal that ensures that the contents of the bag do not spill when the vacuum bag is removed from the apparatus. 
         [0019]    Thus, it is one aspect of the present invention to provide a cleaning assembly for use in a floor cleaning apparatus, comprising: a housing; at least one cylindrical brush having a longitudinal axis positioned within the housing, the longitudinal axis being parallel to the surface being cleaned; a hopper interconnected to the housing; a screen positioned within the hopper that allows particulates of a predetermined diameter to pass therethrough and that prevents particulates of a diameter larger than the particulates of a predetermined diameter from entering the hopper; and a vacuum hose interconnected to the screen wherein the particulates of a predetermined diameter are suctioned into the vacuum hose. 
         [0020]    It is still yet another aspect of the present invention to provide a cleaning assembly, comprising: a means for treating a floor; a hopper associated with said means for treating a floor; a screen positioned within the hopper that allows particulates of a predetermined diameter to pass therethrough and that prevents particulates of a diameter larger than the particulates of a predetermined diameter from entering the hopper; and a vacuum hose interconnected to the screen wherein the particulates of a predetermined diameter are suctioned into the vacuum hose. 
         [0021]    It is another aspect of the present invention to provide an apparatus that employs the features described herein in combination with those of U.S. Pat. No. 7,533,435. For example, a floor treatment apparatus comprising: a chassis having a front and a back and with a lower surface, a front surface adjacent the front, an upper surface, a rear surface adjacent the back, a left surface and a right surface; a first wheel operably interconnected to the lower surface adjacent to the left surface and located closer to the rear surface than the front surface; a second wheel operably interconnected to the lower surface adjacent the right surface and located closer to the rear surface than the front surface; a platform located substantially between at least a portion of the right surface, at least a portion of the left surface and extending rearwardly from a portion of the rear surface, the platform also substantially located within the chassis and positioned substantially directly above an axis extending between the center of the first wheel and the center of the second wheel and wherein the platform includes a top surface which is adapted to receive the feet of an operator, a throttle and an operator presence device operatively connected to and which selectively interrupts operation of the throttle; a powered wheel operably connected adjacent the lower surface of the chassis; a steering mechanism substantially housed within the chassis and having a portion that is accessible by an operator; and an operable floor cleaning assembly connected adjacent to the lower surface of the chassis, the improvement comprising: a hopper associated with the chassis; a screen positioned within the hopper that allows particulates of a predetermined diameter to pass therethrough and that prevents particulates of a diameter larger than the particulates of a predetermined diameter from entering the hopper; and a vacuum hose interconnected to the screen wherein the particulates of a predetermined diameter are suctioned into the vacuum hose. 
         [0022]    The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. The present invention is set forth in various levels of detail in the Summary of the Invention, as well as in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present invention will become more readily apparent from the Detail Description, particularly when taken together with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions. 
           [0024]      FIG. 1  is a rear perspective view of a floor cleaning apparatus of one embodiment of the present invention; 
           [0025]      FIG. 2  is a front perspective view of the apparatus of one embodiment of the present invention wherein some components have been removed for clarity; 
           [0026]      FIG. 3  is a schematic showing the major apparatus components of one embodiment of the present invention and their respective interconnections; 
           [0027]      FIG. 4  is a cross-sectional view depicting the general structure of a cleaning assembly employed by some embodiments of the present invention; 
           [0028]      FIG. 5  is a rear perspective view of a cleaning assembly wherein portions have been removed for clarity; 
           [0029]      FIG. 6  is an exploded perspective view of the hopper of the cleaning assembly; 
           [0030]      FIG. 7  is a rear perspective view of a brush housing; 
           [0031]      FIG. 8  is a detailed perspective view of the apparatus showing a valve in a primary, open position; 
           [0032]      FIG. 9  is a cross-sectional view of  FIG. 7 ; 
           [0033]      FIG. 10  is a detailed perspective view of the valve in a secondary, closed position; 
           [0034]      FIG. 11  is a cross sectional view of  FIG. 9 ; 
           [0035]      FIG. 12  is a partial perspective view of the apparatus showing the attachment hose; 
           [0036]      FIG. 13  is a partial perspective view showing a vacuum bag employed by some embodiments of the present invention; and 
           [0037]      FIG. 14  is a partial front elevation view showing a spring suspension system employed by some embodiments of the present invention. 
       
    
    
       [0038]    To assist in the understanding of one embodiment of the present invention the following list of components and associated numbering found in the drawings is provided herein: 
         [0000]    
       
         
               
               
             
           
               
                   
               
               
                 # 
                 Component 
               
               
                   
               
             
             
               
                  2 
                 Floor scrubber sweeper apparatus 
               
               
                  6 
                 Housing 
               
               
                  10 
                 Vacuum bag 
               
               
                  14 
                 Vacuum motor 
               
               
                  18 
                 Valve 
               
               
                  22 
                 Cleaning assembly 
               
               
                  26 
                 Armature 
               
               
                  30 
                 Accessory hose 
               
               
                  34 
                 Front brush 
               
               
                  38 
                 Rear brush 
               
               
                  40 
                 Motor 
               
               
                  42 
                 Longitudinal axis 
               
               
                  46 
                 Floor 
               
               
                  50 
                 Air path 
               
               
                  54 
                 Opening 
               
               
                  58 
                 Front end 
               
               
                  62 
                 Curved wall 
               
               
                  63 
                 Curved wall 
               
               
                  66 
                 Hopper assembly 
               
               
                  70 
                 Rear wall 
               
               
                  74 
                 Bottom wall 
               
               
                  78 
                 Screen 
               
               
                  82 
                 Fins 
               
               
                  86 
                 Opening 
               
               
                  90 
                 Vacuum hose 
               
               
                  94 
                 Flap 
               
               
                  98 
                 Debris tray 
               
               
                 102 
                 Housing 
               
               
                 106 
                 Brush housing 
               
               
                 110 
                 Opening 
               
               
                 114 
                 Bag hose 
               
               
                 118 
                 Exhaust 
               
               
                 122 
                 Flapper 
               
               
                 126 
                 Hose roller 
               
               
                 130 
                 Capping device 
               
               
                 134 
                 Sealing member 
               
               
                 138 
                 Tab 
               
               
                 142 
                 Spring 
               
               
                   
               
             
          
         
       
     
         [0039]    It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. 
       DETAILED DESCRIPTION 
       [0040]      FIGS. 1-3  show a scrubber/sweeper apparatus  2  (hereinafter “apparatus”) of one embodiment of the present invention that employs a housing  6  that covers a vacuum bag  10 , a vacuum motor  14 , a valve  18 , and other components generally found in floor cleaning apparatus. In addition, the apparatus  2  employs a cleaning assembly  22  that is attached to the housing  6  via a spring to an armature  26 , which will be further described below. In operation, dirt, debris, and residue are agitated by the cleaning assembly  22  and suctioned into the vacuum bag  10 . In a second mode of operation, a hand-held accessory hose  30  is used to suction debris in hard-to-reach places. The debris suctioned through the accessory hose  30  is also directed to the vacuum bag  10  by the vacuum motor  14 . 
         [0041]    Referring now specifically to  FIGS. 4-7 , the cleaning assembly  22  employed by some embodiments of the present invention is shown that includes a front brush  34  and a rear brush  38 . The front brush  34  and rear brush  38  may be comprised of a single, cylindrical brush or a series of stacked cylindrical brushes that are rotated by a motor  40  around a longitudinal axes  42  that are generally parallel to the floor  46  being cleaned. In operation, the front brush  34  rotates counterclockwise (as shown in  FIG. 4 ) and the rear brush  38  rotates clockwise (as shown in  FIG. 4 ). The rotation of the brushes work in conjunction with suction provided by the vacuum motor to define an air path  50  that moves debris from an opening  54  positioned adjacent to the front end  58  of the cleaning assembly  22 , under the front brush  34 , between the front brush  34  and the rear brush  38 , and behind the rear brush  38 . A curved rear wall  62  that is spaced from the rear brush  38  further defines the air path  50 . The rear wall  62  has a larger radius of curvature than the rear brush  38 . In one embodiment, the space between the brush and wall increases wherein the space between the rear wall  62  and the rear brush  38  is greatest at the top of the rear wall  62 . The top of the rear wall creates an opening  110  into the hopper and is positioned at about the same height as the top of the brush so the brush does not capture debris from the hopper  66 . The spacing to the top of the housing (opening size) is about 1 inch. A curved front wall  63  that is spaced from the front brush  34  also helps to define the air path  50 . Similar to the arraignment of the rear brush  38  and the rear wall  62 , the front wall  63  has a slightly larger radius than the front brush  34 . The front wall  63  is positioned so that the space between the front brush  34  and front wall  63  is greatest near the top of the front brush  34 , which helps the movement of debris that may become trapped between the brushes and housing  102 . 
         [0042]    The cleaning assembly  22  also includes a hopper  66  partially comprised a rear wall and a bottom wall  74 . Airflow is directed by the brushes around the curved wall  62  into the hopper assembly  66 . The hopper assembly  66  includes a screen  78  that allows smaller particles and debris to pass to a center opening  86 , but prevents the passage of larger debris from reaching the opening. In one embodiment of the present invention, the screen  78  is comprised of a plurality of fins  82  that are angled such that the airflow and carried debris is directed to a center opening  86  of the screen assembly  78  and which is in fluid communication with the vacuum hose  90 . To increase vacuum and in some embodiments to help to provide the air path  50  shown, a flap  94  may be provided around at least three sides of the cleaning assembly  22 .  FIG. 2  only shows a rear flap  94 , one skilled in the art will appreciate that additional side flaps may be employed to ensure a sufficient vacuum is created to enhance the contemplated air path  50 . The flap  94  is selectively rotatable and thus able to deflect with respect to the cleaning assembly  22  as the apparatus moves over the floor  46 . 
         [0043]      FIG. 6  shows the debris tray  98  that is integrated into the cleaning assembly  22 . The debris tray  98  is selectively interconnected to a brush housing  106  of the cleaning assembly. The debris tray  98  is also concave or angled in such a way that the lowest point is adjacent to the opening  86  provided in the screen. The concave nature ensures that debris will move towards the opening  86  as the cleaning assembly vibrates to be suctioned by the vacuum hose  90 . 
         [0044]      FIG. 7  shows the brush housing  106  that contains the front brush and rear brush. The brush housing  106  is contoured to match the diameter of the brushes, which will enhance the ability of the cleaning assembly to create the contemplated air path. The brush housing  106  provides the elongated opening  110  above the curved walls  62  and  63  that allows air and debris to enter into the hopper. In one embodiment, the opening is about 1 inch wide. 
         [0045]    Referring again to  FIGS. 1-7 , in operation, dirt, dust and debris is pulled from the floor  46  through an opening  54  in the cleaning assembly  22 . The debris-laden air and other particulate matter are directed between counter rotating brushes, over the rear brush  38 , and into the hopper  66 . Large particulates are maintained by the screen  78 , while smaller particulates and dust-laden air are suctioned through the vacuum hose  90 . As one skilled in the art will appreciate, other items such as fluid dispensing devices and scrub brushes may be employed along with this concept to further clean the floor. The air and/or fluid are suctioned through the vacuum hose  90  to a valve  18 . The vacuum motor  14  draws air through the vacuum bag  10  that includes a filter to catch small particles. Air exits the vacuum bag  10  through the vacuum motor exhaust  118 . The exhaust may include a “post filter” to remove additional fine particles and a carbon element to remove odors. To the extent liquid is the fluid which is being collected, it will be deposited in known fashion into a receiving receptacle. 
         [0046]    Referring now to  FIGS. 1-3  and  8 - 12 , the valve  18  and accessory hose  30  of embodiments of the present invention is further described. As mentioned above, the vacuum pressure provided by the vacuum motor  14  suctions air through the vacuum hose  90 . The suctioned air enters into the valve  18  that includes a flapper  122 . When open, ( FIGS. 8 and 9 ), the flapper  122  only allows the debris-laden air from the hopper to be deposited into the vacuum bag  10  via a bag hose  114 . When closed ( FIGS. 10 and 11 ), the flapper  122  allows air from the accessory hose  30  to be deposited in the vacuum bag  10 . The accessory hose  30  may be flexible or otherwise stretchable and is associated with a hose roller  126  interconnected to the housing  6  of the apparatus  2 . In operation, when the end of the accessory hose  30  is closed with a capping device  130 , the accessory hose  30  is retracted within the housing  6  as shown in  FIG. 2 . When in use, the capping device  130  is removed and an accessory is interconnected to the end of the accessory hose. The accessory hose&#39;s flexibility and elongation capabilities allow the user to access debris in hard-to-reach places. 
         [0047]    As shown in  FIG. 13 , the bag hose  114  is interconnected to the vacuum bag  10  that employs a sealing member  134 . The sealing member  134  ensures that when the bag hose  114  is installed, a tight seal is created between the hose and seal. The bag includes a tab  137 , which is designed to mate with protrusion  138  found in the bag holding chamber. The tab  137  and protrusion  138  ensure that the bag is always installed correctly. Also, the bag comes with a seal  139  removably installed thereon. The seal is used to cover the hole in the sealing mechanism when the bag is being replaced or emptied to ensure no debris will spill from the vacuum bag  10 . 
         [0048]      FIG. 14  shows a spring  142  that is interconnected to the armature  26  of the cleaning assembly. The spring  142  provides suspension of the cleaning apparatus. Selectively altering the spring stiffness allows the designer to adjust the force applied to the floor by the brushes. More specifically, the spring stiffness is preferably preselected and is a function of design and cleaning assembly configuration and weight so that the operator can use the machine on many surfaces without adjustment. A long spring, for example, is less sensitive to changes in length and allows for variations in the floor surfaces without significant change to the amount of cleaning assembly weight felt by the floor. 
         [0049]    While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 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.