Abstract:
A mobile floor scrubber sweeper includes operator and engine compartments, clean solution and reclaimed dirty solution tanks, and a clean solution delivery system for applying clean solution to a floor ahead of a pair of counter-rotating cylindrical scrub/sweep brushes. Also included are a debris hopper coupled to a first lift system for moving the debris hopper between an operating position within the scrubber sweeper and an elevated aft position for discharging debris/dirty solution into an external debris container, and a rear squeegee coupled to a second lift system for independently moving the rear squeegee from a lowered, floor engaging, operating position to an elevated non-use position to facilitate squeegee inspection, adjustment, maintenance or replacement, without moving the debris hopper. The hopper and squeegee lift systems operate independently of one another, and the hopper lift system is compatible with standard high, i.e., sixty (60) inch, debris containers.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to mobile floor scrubber sweepers and is particularly directed to an arrangement in a mobile floor scrubber sweeper having a debris hopper and a squeegee, wherein the debris hopper and squeegee are independently and individually movable between a lowered operating position and a range of elevated positions for (1) emptying the hopper into a high debris container, or for (2) inspection, adjustment, maintenance and replacement of the squeegee. 
     BACKGROUND OF THE INVENTION 
     In typical floor care operations, a dedicated floor sweeper is used to remove dry fine and bulky solid debris from the floor. When necessary, a dedicated floor scrubber trails the sweeper to scrub the floor to a shiny finish. As typically happens between the time the sweeper has completed a pass and the arrival of the scrubber, additional debris is deposited on the floor. When the dedicated floor scrubber passes over this later deposited debris, the debris is engaged by and gets caught in the rear squeegee in the scrubber, reducing the performance of the squeegee by causing solution loss and floor streaking. In addressing this problem, combined scrubber sweepers have been developed that are essentially a floor scrubbing machine which is also provided with a limited sweeping capability. These combined machines use the rotating rear cylindrical scrub brush, or brushes, as a sweeping broom which picks up solid debris and directs the debris into a hopper. This arrangement prevents solid debris from becoming trapped in the rear squeegee causing the aforementioned solution loss and streaking on the floor. 
     In many combined scrubber sweeper machines, the debris hopper is manually removed from the machine, lifted to a raised position, and emptied by hand into a debris dumpster. The substantial weight of wet debris limits the maximum capacity of debris hoppers emptied by hand. In some cases, the debris hopper of the scrubber sweeper machine is in the form of two separate hoppers to facilitate manual lifting and emptying of each hopper. The manual lifting and emptying of a debris hopper is particularly a problem when attempting to empty the debris hopper into a standard high debris dumpster which is typically on the order of sixty (60) inches high. 
     To provide larger debris hopper capacity for increasing scrubber sweeper machine productivity by increasing the time between the required emptying of the debris hopper, high dump scrubber sweepers have been developed which incorporate powered debris emptying systems. These systems typically have the ability to raise the hopper to a sufficient height for emptying into standard 60″ high debris dumpsters. In these types of combined scrubber sweeper cleaning machines, the aft squeegee operates to retain water between itself and a front squeegee, where it is vacuumed up through a vacuum port. The rear squeegee is typically comprised of rubber and operates as a seal as it is dragged against the floor, tending to wear out and require replacement. This characteristic necessitates frequent inspection, adjustment, maintenance and replacement of the rear rubber squeegee. This presents a problem in existing scrubber sweeper machines as removing and replacing the rear rubber squeegee in a scrubber sweeper mounting structure is quite awkward and time consuming. This presents an efficiency/productivity problem because of the necessity for frequent inspection, adjustment, maintenance and replacement of the rear rubber squeegee. 
     The present invention addresses the aforementioned problems of the prior art by providing for the powered, independent movement of the scrubber sweeper&#39;s debris hopper and the scrubber sweeper&#39;s rear squeegee between a lowered operating position and a range of elevated positions to facilitate either emptying of the debris hopper into a debris dumpster as high as 60″ dumpster, or higher, or inspection, adjustment, maintenance and possible removal and replacement of the squeegee. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is in an object of the present invention to provide a mobile high dump floor scrubber sweeper with separate displacement systems for raising and lowering the scrubber sweeper&#39;s debris hopper and squeegee assembly independently from one another. 
     It is another object of the present invention to provide the capability in a mobile floor scrubber sweeper having a floor squeegee assembly to move the squeegee assembly between a lowered use position within the scrubber sweeper and an elevated non-use position which is displaced from the sweeper assembly and other components and assemblies of the scrubber sweeper for facilitating inspection, adjustment, maintenance and replacement of the squeegee. 
     Yet another object of the present invention is to provide a first lift system in a mobile floor scrubber for lifting the scrubber sweeper&#39;s debris hopper to an elevated position for discharge of the debris into a high debris dumpster debris, and a second lift system for lifting the scrubber sweeper&#39;s rear squeegee from the floor to an elevated position spaced from the debris hopper to facilitate inspection, adjustment, maintenance and replacement of the squeegee. 
     More particularly, the present invention is directed to an industrial rider scrubber sweeper used to clean floors. The scrubber sweeper is equipped with an operator compartment, an engine compartment, a cleaning solution tank, a solution delivery system that applies cleaning solution to the floor ahead of one or more rotating cylindrical scrub brushes, a debris hopper located directly behind the scrub brushes, a first powered debris hopper lift system, a rear squeegee assembly, and a second squeegee lift system for raising the squeegee over a range of elevated positions to facilitate squeegee inspection, adjustment, maintenance and replacement without interference with an elevated debris hopper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will best be understood by reference to the following detailed description of a preferred embodiment taken in conjunction with the accompanying drawings, where like reference characters identify like elements throughout the various figures, in which: 
         FIG. 1  is a simplified longitudinal sectional view of a floor scrubber sweeper machine shown in the operating, floor cleaning configuration in accordance with the present invention; 
         FIG. 2  is a simplified longitudinal sectional view of the present invention showing the debris hopper and squeegee in fully upraised positions; 
         FIG. 3  is a lateral view of the inventive floor scrubber sweeper machine shown in the operating, floor cleaning configuration; 
         FIG. 4  is a lateral view of the inventive floor scrubber sweeper machine showing the squeegee in the fully upraised position and the hopper in the lowered, use position; 
         FIG. 5  is a lateral view of the inventive floor scrubber sweeper machine showing both the debris hopper and squeegee in fully upraised positions; 
         FIG. 6  is a front plan view of the inventive floor scrubber sweeper machine; 
         FIG. 7  is an aft plan view of the inventive floor scrubber sweeper machine showing the debris hopper in the full down, operating positions and the squeegee in raised, transparent position; 
         FIG. 8  is an aft right perspective view of the inventive floor scrubber sweeper machine with the squeegee removed for more clearly showing the debris hopper in the full up position; 
         FIG. 9  is an aft left perspective view of the inventive floor scrubber sweeper machine with the squeegee removed for more clearly showing the debris hopper in the full up position; 
         FIG. 10  is a perspective view of the debris hopper in the full up position; 
         FIG. 11  is an aft perspective view of the debris hopper with the debris hopper in the full up position; 
         FIG. 12  is a perspective view of the squeegee shown in a partially upraised position such as for inspecting, adjusting, maintaining or replacing the squeegee; 
         FIG. 13  is a simplified perspective view illustrating the floor scrubber sweeper machine&#39;s frame, engine, high dump hydraulic manifold and high dump electrical system in one embodiment of this invention; 
         FIGS. 14 and 15  are perspective views of an arrangement for securely maintaining the debris hopper or the squeegee in a fixed upraised position; and 
         FIGS. 16 and 17  are schematic diagrams of a hydraulic system for raising and lowering the scrubber sweeper&#39;s debris hopper and squeegee in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1-7 , the inventive floor scrubber sweeper machine  10  will now be described in detail. As shown in the simplified longitudinal sectional views of  FIGS. 1 and 2 , scrubber sweeper machine  10  includes a chassis  12  having an operator compartment  14  which includes, among other things, a steering wheel  14   a . Also disposed within chassis  12  is the combination of an engine  16  for propulsion and a radiator  18  for controlling the operating temperature of the engine. Disposed within chassis  12  is also a clean solution tank  22  containing a cleaning solution  23  which is deposited via a cleaning solution discharge conduit  22   a  on the floor  17  being cleaned forward of the combination of forward and aft cylindrical scrub brushes  26   a ,  28   a . The forward and aft cylindrical scrub brushes  26   a ,  28   a  are rotationally displaced in opposing directions as shown by direction arrows  26   b  and  28   b . The counter-rotation of the forward and aft cylindrical scrub brushes  26   a  and  28   a  causes debris, including dirty water on the surface of the floor, to be projected upwardly between the two rotating scrub brushes and rearwardly by the forward movement of the scrubber sweeper machine  10  and the contour of its undercarriage  21 . The debris displaced by the forward and aft cylindrical scrub brushes  26   a  and  26   b  is directed into the open forward portion of a debris hopper  30 , which debris as shown as element  32  in  FIG. 1 . Hopper  30  includes a forward pivoting door  60 . 
     The fluid, or water,  32  within hopper  30  is drawn upwardly in the direction of arrows  34   a  and  34   b , as shown in  FIG. 1 , by means of the suction action of a vacuum fan  56  disposed in an upper portion of a machine&#39;s chassis  12 . Also disposed in an aft portion of chassis  12  is the combination of a rear squeegee  44  and a squeegee vacuum hose  46  as also shown in  FIG. 1 , where the rear squeegee is shown disposed in contact with the surface of floor  17 . The fluid collected by squeegee  44  is drawn up through the squeegee vacuum hose  46  and into a reclaimed dirty solution tank  24 , where arrow  42  illustrates the flow of collected fluid from the squeegee vacuum hose and into the reclaimed dirty solution tank. A demister  48  disposed in an upper, aft portion of chassis  12  removes mist and vapor from the extracted air and directs it in the direction of arrow  54 . The air thus drawn by vacuum fan  56  is discharged from the floor scrubber sweeper  10  and into the atmosphere as shown by flow direction arrow  58 . 
     With reference to  FIG. 2 , debris hopper  30  and squeegee  44  are shown in the full up position. The hopper&#39;s door  30   a  is shown in the closed position so as to retain the debris and fluid within the hopper  30 . By moving the hopper door  30   a  to the position where it is shown in dotted line form, the fluid and debris is discharged from the hopper  30  under the influence of gravity. Also as shown in  FIG. 2 , squeegee lift arm  38  and hopper lift arm  58  are fully elevated to maintain the hopper  30  and squeegee  44  in their fully elevated positions. Also shown is the flexible squeegee vacuum hose  46  coupling squeegee  44  to the dirty solution tank  24  located in an aft portion of the scrubber sweeper&#39;s chassis  12 . 
       FIG. 3  is a side elevation view of the floor scrubber sweeper machine  10  with its debris hopper  30  and its rear squeegee  44  shown in the full down, use position, and with the squeegee lift arm  38  and the debris hopper lift arm  58  aligned in closely spaced, parallel vertical alignment.  FIG. 4  is a side elevation view of the inventive floor scrubber sweeper machine  10  showing only its rear squeegee  44  in the full up position, with its debris hopper  30  shown in the full down, operating position.  FIG. 5  is also a side elevation view of the inventive floor scrubber sweeper machine  10  showing both debris hopper  30  and squeegee  44  in the full up position, with the hopper&#39;s door  30   a  in the open position to allow for the discharge of debris from the hopper into a high, typically 60″, debris dumpster  31 .  FIG. 6  is a front plan view of the inventive floor scrubber machine  10  illustrating its three wheels  20   a ,  20   b  and  20   c , as well as a radiator grill  19  disposed on a forward portion of the machine&#39;s chassis  12 . The machine&#39;s front wheel  20   a  provides a steering capability and propulsion.  FIG. 7  is an aft plan view of the inventive floor scrubber sweeper machine  10  with its debris hopper  30  and its rear squeegee  44  in an upraised position. Also shown in  FIG. 7  is the squeegee vacuum hose  46 , as well as a recovery, or reclaimed dirty solution, tank drain hose  64  coupled to the above described recovery tank  24 . Also illustrated in  FIG. 7  is a clean solution drain hose  68  coupled to the above-described clean solution tank  22  for allowing for draining clean solution from the clean solution tank. 
     Referring to  FIGS. 8, 9, 10 and 11 , there are shown various perspective views of the debris hopper  30  in the full up position. Attached to the debris hopper  30  are first and second support arms  27   a  and  27   b . Respective first ends of each of the first and second support arms  27   a ,  27   b  are pivotally coupled to an aft, upper portion of chassis  12  by means of a respective pivot pin, where pivot pin  29  is shown in  FIG. 10  pivotally coupling first support arm to an aft upper portion of the chassis. Second, opposed ends of each of the first and second support arms  27   a  and  27   b  are securely coupled to respective lateral portions of the debris hopper  30 . Pivotally coupled to respective intermediate portions of each of the first and second support arms  27   a ,  27   b  is a respective telescoping tube or hydraulic cylinder as described below. 
     More specifically, respective intermediate portions of the squeegee&#39;s first and second support arms  58   a  and  58   b  are coupled to respective first ends of a first hydraulic cylinder  78   a  and to a first telescoping tube  78   b . Similarly, respective intermediate portions of the debris hopper&#39;s first and second support arms  27   a  and  27   b  are coupled to a second telescoping tube  76   a  and to a second hydraulic cylinder  76   b . The first hydraulic cylinder  78   a  raises and lowers squeegee  44 , while second hydraulic cylinder  76   a  raises and lowers hopper  30 . The second telescoping tube  76   a  provides support and alignment for the debris hopper  30 , while the first telescoping tube  78   b  provides support and alignment for squeegee  44 . As shown in  FIGS. 14 and 15 , the second telescoping tube  76   a  includes an upper, inner tube  202   a  and a lower, outer tube  202   b  coupled together in a sliding manner to allow the tube&#39;s length to change. Aligned apertures  200  are disposed in a spaced manner in the upper, inner and outer, lower tubes  202   a  and  202   b , and are adapted to receive a safety pin  96  for maintaining the debris hopper  30  and/or the squeegee at an elevated position in a fixed manner. A support bracket  204  is attached to an outer portion of lower tube  202   b  and is adapted to receive safety pin  96  for storage as shown in  FIG. 15 . 
     As shown in  FIG. 10 , debris hopper  30  includes a hydraulic cylinder  30   c  for opening and closing the hopper&#39;s door  30   a . Disposed on an aft portion of the debris hopper  30  is a hopper suction hose seal plate  86  which is adapted for sealed coupling to a suction hose attached to the recovery tank drain hose  64 . Debris hopper  30  includes a lower removable clean out cover  88  for removing debris adhering to the inside of hopper  30 . In addition, hopper door  30   a  is provided with a door seal  92  for preventing discharge of debris from the hopper when the door is closed. Provided at a lower, lateral portion of chassis  12  is a clean out cap  84  for removing residual debris from the recovery tank  24 . 
       FIG. 11  is an aft perspective view of the inventive floor scrubber sweeper machine  10  with its hopper  30  as well as its rear squeegee (not shown in the figure for simplicity) in the full up position. As described above, hopper  30  is supported and displaced by means of the combination of the second telescoping tube  76   a  and second hydraulic cylinder  76   b  and first and second support arms  27   a  and  27   b . Similarly, squeegee  44  is supported and displaced by means of third and fourth support arms  58   a  and  58   b  in combination with first hydraulic cylinder  78   a  and first telescoping tube  78   b . The pair of squeegee support arms  58   a ,  58   b  are disposed inside of the pair of hopper support arms  27   a  and  27   b . Extension of the second hydraulic cylinder  76   b  raises support arms  27   a  and  27   b  as well as debris hopper  30 , while retraction of this hydraulic cylinder lowers the combination of the first and second support arms and also lowers the hopper. Similarly, extension and retraction of second hydraulic cylinder  78   a  raises and lowers the combination of third and fourth support arms  58   a  and  58   b , as well as squeegee  44 . 
     Referring to  FIG. 12 , there is shown a perspective view of squeegee  44  in an intermediate elevated position to facilitate inspection, adjustment, maintenance or replacement of the squeegee. First and second rollers  94   a  and  94   b  are attached to and disposed adjacent respective opposed ends of bumper  80 . These rollers  94   a  and  94   b  are adapted for engaging and facilitating displacement along walls during operation of the floor scrubber sweeper machine  10 . The squeegee&#39;s vacuum hose  46  has been omitted from  FIG. 12  for the purpose of clarity. As shown in  FIG. 12 , squeegee  44  is concave in the direction of travel of the floor scrubber sweeper machine  10  during operation. 
     Referring to  FIG. 13 , there is shown a perspective view of the scrubber sweeper machine&#39;s frame  100 , clean solution tank  22 , vacuum fan, or impeller,  56 , as well as its engine  16 . Also shown in  FIG. 13  is its high dump hydraulic manifold  102 , its high dump electrical components  104  and hydraulic pumps  106 . The operation of these various components is described in detail in the following paragraphs. 
     Referring to  FIGS. 16 and 17 , there is shown a hydraulic system  118  for use in the disclosed embodiment of the present invention. Hydraulic system  118  includes a hydraulic fluid reservoir  120  coupled to a propulsion pump  126 . Propulsion pump  126  provides propulsion for the inventive scrubber sweeper machine  10  and is coupled to an auxiliary pump  128  which includes three individual pumps. A first pump is coupled via a first hydraulic line  130  to a vehicle steering unit  136  which, in turn, is coupled to a steering cylinder  138 . The output of the steering unit  136  is provided to the steering cylinder  138  which controls the position of the vehicle&#39;s front wheel  20   a  in response to operator inputs. Hydraulic reservoir  120  is further coupled to auxiliary pump  128  via a hydraulic fluid strainer  122 . A second output from a second pump within auxiliary pump  128  is provided via a second hydraulic line  134  to a vacuum fan manifold  140  for controlling the operation of the previously described vacuum fan  56  which is connected to the high dump hydraulic manifold  102 . 
     A third output from the auxiliary pump  128  from a third pump therein is provided via a third hydraulic line  134  to a main manifold  142 . This output from the auxiliary pump  128  is more specifically provided to an ALL OFF solenoid valve  146 . Main manifold  142  further includes a MAIN BRUSHES ON-OFF solenoid valve  148  which operates in conjunction with the ALL OFF solenoid valve  146  to control the operation of the forward and aft cylindrical scrub brushes  26   a ,  26   b . With the ALL OFF solenoid valve  146  off, this valve transmits hydraulic fluid. Fluid to the scrub brushes  26   a  and  28   a  is blocked and returned to the hydraulic reservoir  120  via hydraulic line  25 . With both of the ALL OFF and MAIN BRUSHES ON-OFF solenoid valves  146 ,  148  energized, the ALL OFF solenoid valve blocks the flow through return path  25  and the MAIN BRUSHES ON-OFF solenoid valve allows the fluid to go to the brushes. Main manifold  142  further includes a BRUSH FORCE solenoid valve  150  and a MAIN BRUSHES DOWN solenoid valve  152  for controlling the downward pressure to be applied by the forward and aft cylindrical scrub brushes  26   a ,  28   a  to the floor being cleaned. Control of the operation of the combination of BRUSH FORCE solenoid valve  150  and MAIN BRUSHES DOWN solenoid valve  152  is provided by means of an operator controlled free position rotary switch which is not shown in the figure for simplicity. If the operator selects a downward pressure of 865 pounds per square inch (psi), the pressure applied to the upper portion of a squeegee cylinder  154  works in conjunction with the 450 psi applied to the bottom of the squeegee cylinder via the combination of a squeegee up-down solenoid valve  162  and a control valve  164  so that a maximum downward pressure is exerted by the forward and aft scrub brushes  26   a ,  28   a  on the floor being cleaned. Similarly, selection of an intermediate downward pressure or a minimum downward pressure by means of the BRUSH FORCE 100-800 psi solenoid valve  150  results in either in intermediate or a minimum downward pressure being exerted by the scrub brushes on the floor via a brush lift cylinder  156 . In summary, the amount of pressure applied via the BRUSH FORCE 100-800 psi solenoid valve  150  and the MAIN BRUSHES DOWN solenoid valve  152  to the upper portion of the BRUSH LIFT CYLINDER  156  controls and determines the amount of downward pressure applied by the brushes to the floor, which downward force works in conjunction with the upward force applied to the lower portion of the BRUSH LIFT CYLINDER via the combination of the reduction valve  158  and MAIN BRUSHES UP-LOCK solenoid valve  160 . In addition, the MAIN BRUSHES UP-LOCK solenoid valve  160  performs the function of maintaining the elevation of the brush when in the non-use position following shut down of the scrubber sweeper machine  10 . If the MAIN BRUSHES DOWN solenoid valve  152  is off, the output of the MAIN BRUSHES UP-LOCK solenoid valve  160  to the lower portion of the BRUSH LIFT CYLINDER  156  automatically raises the elevation of the forward and aft scrub brushes  26   a ,  28   a  to on the order of six inches above the floor engaging position during operation. Main manifold  142  further includes a SQUEEGEE UP-DOWN solenoid valve  162  in combination with a check valve solenoid  164  which are coupled to squeegee cylinder  154  for controlling an intermediate height of the squeegee  44  above the floor. SQUEEGEE UP-DOWN solenoid valve  162  is controlled by electrical inputs from the machine operator to operate in a first mode wherein hydraulic fluid is provided via the solenoid valve to an upper end of the squeegee cylinder  154  for urging the squeegee to the lower, use position wherein the squeegee engages the floor. Alternatively, the operator may select a second input to the SQUEEGEE UP-DOWN solenoid valve  162  so as to provide hydraulic fluid via a check valve  164  to a lower portion of the squeegee cylinder  154  for urging the squeegee to a higher, non-floor engaging position when the squeegee is not in use such as when the floor scrubber machine is in transport. As shown in  FIG. 16 , there is one output from the hydraulic system  118  in the form of a power output, or power beyond (PB), via line  166  and one input in the form of “B” via line  168 . 
     Referring specifically to  FIG. 17 , there is shown an additional portion of the hydraulic system  118  shown in  FIG. 14 . The portion of the hydraulic schematic shown in  FIG. 1  is hydraulically coupled to the hydraulic system  118  of  FIG. 16  in that it receives power beyond an output B to the B input of the hydraulic system  118  shown in  FIG. 16 . The hydraulic system in  FIG. 17  includes a secondary manifold  165  coupled to a squeegee lift arm hydraulic cylinder  186 , a hopper lift hydraulic cylinder  188  and a hopper door hydraulic cylinder  190 . Secondary manifold  165  includes first, second and third hydraulic switches  180 ,  182  and  184 . The first and second hydraulic switches  180 ,  182  are respectively coupled to the squeegee lift arm hydraulic cylinder  186  and to the hopper lift hydraulic cylinder  188 . The first and second switches  180 ,  182  are identical in configuration and operation. Therefore, only the operation of the first switch  180  is described in detail herein, it being understood that the second switch  182  operates in the same way to achieve the same end results with regard to the operation of the hopper lift hydraulic cylinder  188 . 
     The first switch  180  includes a squeegee lift arm raise solenoid valve  170  and a squeeze lift arm lower solenoid valve  171 . When a squeegee lift arm control button  189  is selected, the appropriate input is provided to solenoid valve  170  so that hydraulic fluid passes through check valve  174  to a lower portion of the squeegee lift arm hydraulic cylinder  186  as shown in  FIG. 17 , so as to cause the squeegee lift arm hydraulic cylinder to raise the squeegee&#39;s support arms  58   a ,  58   b . Upward movement of the squeegee  44  and its associated support arms  58   a ,  58   b  is stopped at the specified, or desired, height, or elevation, by closing check valve  174 . Squeegee  44  remains at that designated height until additional hydraulic fluid is provided to the squeegee lift arm hydraulic cylinder  186 . The hydraulic fluid orifice port controls discharge of hydraulic fluid from the squeegee lift arm hydraulic cylinder  186  so as to allow the squeegee to descend slowly such as in the event of breakage or leakage of a hydraulic fluid line. The squeegee  44  is lowered by pressing a lower position control button selector  189  to allow hydraulic fluid to pass via upper check valve  172  to an upper portion of the squeegee lift arm hydraulic cylinder  186 , while at the same time lower check valve  174  prevents the flow of hydraulic fluid from the lower portion of the squeegee lift arm hydraulic cylinder  186  to allow for lowering of squeegee  44 . Thus, when hydraulic fluid is applied only to check valve  172  or only to check valve  174 , the other check valve is opened allowing the change in the direction of motion of the squeegee  44 . Each of the first and second check valves  172 ,  174  locks the squeegee lift arm hydraulic cylinder  186  in a fixed position until a new input is provided via the first switch  180  to the squeegee lift arm hydraulic cylinder  186 . As indicated above, second switch  182  performs the same function in the same manner with respect to the hopper lift hydraulic cylinder  188  as the first switch  180  does to the squeegee lift arm hydraulic cylinder  186 . As first switch  180  is coupled to the first control button  189 , second switch  182  and third switch  184  are respectively coupled to second and third control buttons  191  and  193 . 
     The third switch  184  includes a hopper door open-close hydraulic switch valve  192  for controlling the opening and closing of the door  30   a  of the debris hopper  30 . Thus, an input to the hopper door open-close solenoid valve  192  is provided via line PB from the hydraulic system  118  shown in  FIG. 16 . With the hopper door open-close solenoid valve  192  turned off, and with the hydraulic system pressurized, pressure is applied to both sides of the hopper door hydraulic cylinder  190  which closes the debris hopper&#39;s door  30   a . Just before the hopper  30  is raised, there is a timer (not shown) which times out to allow hydraulic pressure to be applied via the hopper door open-close solenoid valve  192  to the rod end, or lower end as shown in  FIG. 17 , of the hopper door hydraulic cylinder  190  so that it opens the debris hopper&#39;s door  30   a . There is no switch for opening the debris hopper door  38 , just for closing the door which is spring loaded to the OFF position. Thus, the debris hopper&#39;s door  38  is always open as the floor scrubber sweeper machine  10  is operating. Check valve  194  prevents opening of the debris hopper&#39;s door  38  when in a closed position. 
     In summary, each of the two lift arm assemblies is comprised of a respective pair of spaced support arms and has its own raise/lower hydraulic cylinder and telescoping tube which serves as a safety tube. The hydraulic cylinders  76   b  and  78   a  are used not only to raise the squeegee  44  and debris hopper  30 , but also to lower the squeegee and debris hopper. Because the squeegee  44  and debris hopper  30  centers of gravity, when lowered, are forward of the lift arm pivot point, the squeegee and hopper do not fully retract due to gravity alone so that the pair of aforementioned hydraulic cylinders are used to fully retract the squeegee and hopper. As described above, each of the telescoping tubes  76   a  and  78   b  include a respective safety pin  96  that can be inserted at three different lift arm heights, i.e., a low position, a medium height position, and a fully upraised position. Also as described above, the hydraulic cylinder  78   a  that powers the squeegee support arm assembly is located on the left side of the floor scrubber sweeper machine  10 , while its&#39; associated telescoping tube  78   b  is located on the right side of the machine. Similarly, the hydraulic cylinder  76   b , which powers the hopper support arm assembly, is located on the right side of the floor scrubber sweeper machine  10 , while its&#39; associated telescoping tube  76   a  is located on the left side of the machine. Squeegee  44 , as described above, can be raised separately from the debris hopper  30 , which is particularly useful when inspecting or performing maintenance on the squeegee. If desired, both of the squeegee and hopper support arm assemblies can be raised and lowered at the same time. The outer hopper support arm assembly is provided with a solenoid-operated latch  116 , located at the lower end of the right lift arm  76   b  as shown in  FIG. 11 . This latch  116  ensures that the lift arms stay in place while the machine is moving as during scrubbing operations. The squeegee lift arm assembly is also provided with a tilt switch  114  located on the lower end of the left lift arm  78   a . If the operator raises and then lowers the debris hopper  30  without opening its dump door  30   a , tilt switch  114  will open the hopper dump door automatically when the hopper is within 15° of the fully lowered position such as shown in  FIG. 1 . An “interference” switch is located on the lower end of the inner (hopper) lift arms which prevents the hopper lift arms from contacting the squeegee lift arms when the squeegee lift arms are not fully raised. 
     Referring again to  FIG. 17 , there are shown a lift bumper/squeegee neutral switch  180 , a center hopper control switch  182 , and a right hopper dump door switch  184 . The left bumper/squeegee switch  180  includes a squeegee lift arm raise valve  170  and a squeegee lift arm lower solenoid valve  170  in combination with first and second check valves  172  and  174  for controlling the squeegee lift arm cylinder  186 . Center switch  182  operates in the same way and includes the same components to control the raising and lowering of the hopper lift cylinder  188 . The hopper dump door switch  184  includes the combination of a hopper door open-closed solenoid valve  192  and a check valve  194  for controlling the opening and closing of the hopper door via a hopper door cylinder  190 . The hopper dump door switch  184  functions as a two-position rocker switch having a front “door open” position and a rear “off” position, where the switch is spring loaded to the “off” position. There is no “door closed” position. 
     Pressing and holding the front of the first squeegee switch  180  causes the solenoid-operated latch to release and raise the two squeegee lift arms  78   a  and  78   b . Squeegee  44  can be raised to its full height, where it can be stopped at any desired intermediate height by releasing the first squeegee switch  180 . A pilot-operated check valve  174  maintains the squeegee lift arm assembly in place when raised. Pressing and holding the rear of the first switch  180  lowers the squeegee lift arms  78   a ,  78   b.    
     Pressing and holding the front of the second hopper switch  182  causes the solenoid-operated latch to release and raise the squeegee lift arms  78   a  and  78   b . The squeegee  44  can be raised to its full height, or can be stopped at any intermediate height by releasing the second hopper switch  182 , with a pilot-operated check valve  191  which holds the squeegee lift arm assembly in place when raised. Pressing and holding the rear of the first squeegee switch  180  lowers the squeegee lift arms. 
     Placing and holding the front of the third hopper door switch  184  for three seconds opens the dump door  30   a  of the hopper  30 . This switch is used only for emptying the contents of the hopper  30 . The remaining hopper dump door operation is automatic, with the dump door always automatically opened during scrubbing operations. Just before the hopper lift arm assembly begins to raise, the hopper dump door  38  automatically closes. If the hopper contents are emptied such as by pressing the front of the third hopper door switch  184 , the hopper door will remain open when lowered. If the hopper  30  is lowered without opening the hopper door  30   a , the door will be automatically opened by the tilt switch. 
     The safety pins  96  described above should always be inserted into the telescoping tubes  76   a  and  78   b  when working under, or around, the raised squeegee  44  or debris hopper  30 . After raising the squeegee  44  and debris hopper  30  to the desired height, the safety pins  96  should be removed from a support bracket  204  and they should be inserted into an appropriate pair of apertures within the telescoping tube depending upon the raised height of the squeegee and debris hopper, i.e., a lower “maintenance” position, a medium height position, or the fully raised position. It is not necessary to “lock” the safety pin  96  in place by lowering the squeegee  44  or debris hopper onto the safety pin. However, if the squeegee or hopper lift arms are lowered onto a pair of the safety pins, relief valves prevent the hopper and squeegee hydraulic cylinders  76   b  and  78   a  from causing any damage to the hopper or squeegee lift arms, or to any adjacent structure. 
     The dual lift arm system for the hopper and squeegee of a mobile floor scrubber sweeper disclosed herein has the substantial advantage of providing the operator and a maintenance person with the ability to raise, or partially raise, only the squeegee assembly. The squeegee  44  is the key element in removing solution from the floor, and as such, requires specific attention. Being able to raise only the squeegee  44  without moving the debris hopper  30  provides heretofore unmatched and unavailable clear open access to the squeegee and associated components for inspection, adjustment, maintenance or replacement of the squeegee. 
     While particular embodiments of the present invention have been described, it will be obvious to those skilled in the relevant arts that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications that fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper prospective based on the prior art.