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RELATED APPLICATION 
     This application claims the benefit of priority of U.S. Provisional Patent Application No. 60/292,683, filed on May 21, 2001, the disclosure of said application being incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to floor maintenance or conditioning machines, and particularly those machines employing one or more floor maintenance or conditioning appliances or tools that perform one or more tasks including, among others, scrubbing, sweeping, and polishing or burnishing. More particularly the invention is directed to an apparatus for coupling a floor maintenance appliance to a floor maintenance machine. 
     BACKGROUND OF THE INVENTION 
     Surface maintenance machines that perform a single surface maintenance or surface conditioning task are, of course, well known. Surface maintenance machines are generally directed to applications such as floor surfaces, or simply floors. The term floor, as used herein, refers to any support surface, such as, among others, floors, pavements, road surfaces, ship decks, and the like. 
     Commonly floor or surface maintenance machines are constructed having a single surface conditioning appliance or system so as to only sweep, others to scrub, while still others only to polish or burnish. It is of course possible to construct a single surface maintenance machine to perform one or more of the aforementioned surface maintenance tasks. 
     One example of a multi-task floor or surface conditioning machine is disclosed in U.S. Pat. No. 3,204,280, entitled, “Floor Cleaning &amp; Waxing Machine,” issued to Campbell, the entire disclosure of which is incorporated by reference herein in its entirety for any and all purposes. Another is disclosed in U.S. Pat. No. 4,492,002 entitled, “Floor Cleaning Machine,” in name of inventors Waldhauser, et al, the entire disclosure of which is incorporated by reference herein in its entirety for any and all purposes. Disclosed therein is a forward sweeper assembly followed by a scrubber assembly that is followed by a squeegee assembly. 
     Yet, another example of a multi-task floor conditioning machine is disclosed in a PCT applications having publication WO 00/74549, published 14 Dec. 2000, entitled, “Floor Cleaning Machine,” in name of inventors Thomas, et al, the entire disclosure of which is incorporated by referenced herein in its entirety for any and all purposes. The machine disclosed therein performs the task of sweeping, scrubbing, and burnishing, and includes a squeegee assembly in combination with a vacuum system for removing cleaning solution from a floor subsequent to a cleaning and scrubbing operation. 
     As illustrated in WO 00/74549, thereshown is a single unitary walk-behind machine that is transportable across a floor. Successively attached to the machine, from front to back, are independent floor maintenance systems. At the forward section of the machine is a sweeping system. At the rearward section of the machine-machine steering control-is a burnishing system. In between the sweeping system and the burnishing system is a scrubbing system including forward scrubbing brushes coupled to a cleaning solution dispensing system and rearward following squeegees coupled to a liquid vacuum system for recovering expended cleaning solution. 
     Burnishing systems generally include a scheme for controlling the degree of burnishing applied to a floor surface depending upon the type of floor surface intended to be burnished. Burnishing systems well known in the art commonly include a driver assembly which includes a working appliance or tool such as a pad or brush affixed to a driver that is rotatably driven by a driver motor. The driver assembly of the burnishing systems of the prior art have been selectively raised and lowered by an actuator so as to achieve an intended force or pressure against a floor surface intended to be polished or burnished. 
     Scrubbing systems are analogous to burnishing systems, and are also well known in the art. Scrubbing systems commonly include a driver assembly including rotatable scrubber in the form of a brush, pad, or the like, and a scheme for controlling the degree of scrubbing applied to a floor surface depending upon the type of floor surface intended to be scrubbed. Too much scrubbing of course may deleteriously affect the floor surface requiring further maintenance. The scrubber driver assemblies for scrubbing systems, like burnishing systems, are of course well known in the art and commonly include one or more rotatable brushes driven by a driver motor affixed to a scrubber head. Scrubber heads of the prior art have been selectively raised and lowered by an actuator coupled to the driver so as to achieve an intended force or pressure of the brush against a floor surface intended to be scrubbed. Examples of the latter are taught in U.S. Pat. Nos. 4,757,566; 4,769,271; 5,481,776; 5,615,437; 5,943,724 and 6,163,915, each patent being incorporated in its entirety by reference herein. 
     Sweeper systems are also analogous to burnishing systems. Sweeper systems commonly include a rotatable sweeper system brush driven by a driver motor. Like burnishing and scrubbing systems the sweeper system brush may be lowered and raised relative to a floor, which may more or less affect the floor surface. 
     Commonly, floor conditioning machines are powered by a rechargeable battery supply. Of course, the battery voltage applied to the various floor conditioning systems or appliances, and particularly to the driver motor, will decay in relation to the energy discharged by the battery and the total time of discharge. With respect to burnishing systems, the mechanical burnishing power delivered to the floor is therefore dependent upon the voltage and current delivered to the driver motor. 
     Coupling devices including 4 bar linkages are known in the prior art to connect a working tool or appliance to a surface maintenance machine. One such device is disclosed in U.S. Pat. No. 5,455,985, the disclosure of which is incorporated in its entirety by reference herein. 
     SUMMARY OF THE INVENTION 
     An overhead suspension system for a floor maintenance appliance is disclosed herein. In one exemplary embodiment of the present invention, an overhead suspension system may be utilized to suspend a brush assembly and a hopper assembly from a floor maintenance machine. In an exemplary embodiment of the present invention, the brush and hopper assemblies can be transitioned away from a floor surface upon contact with an obstacle or surface irregularity, substantially preventing damage to the brushes or hopper. Because the suspension is overhead, the brushes and hopper can be lifted up into the boundaries of the frame of the floor maintenance apparatus, avoiding being damaged. 
     An objective of the present invention is to provide an overhead suspension system that is responsive to surface obstacles to obviate damages to the machine. 
     Another objective of the invention is to provide an overhead suspension system that is simple to maintain and fabricate. 
     Another object of the present invention is an overhead suspension system which may be utilized to couple a variety of different floor maintenance appliance to a floor maintenance machine 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a multi-task surface maintenance machine of the prior art illustrating a front sweeper system followed by a scrubber system, followed by a burnishing system illustrated in WO 00/74549. 
         FIG. 2  is a perspective view of the prior art sweeper system illustrated in WO 00/74549. 
         FIG. 3  is a wire design drawing illustrating a plan view of the sweeper system in accordance with the present invention. 
         FIG. 4  is a wire design drawing illustrating a side view of the sweeper system in accordance with the present invention in the normal operative condition. 
         FIG. 5  is a wire design drawing illustrating a side view of the sweeper system in accordance with the present invention in an obstacle response position. 
         FIG. 6  is a wire design drawing illustrating a side view of the sweeper system in accordance with the present invention in the transport position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Illustrated in  FIG. 1  is a walk behind surface conditioning machine  10  known in the art and disclosed in WO 00/74549. A burnishing assembly generally indicated by numeral 16, scrubbing assembly  14 , and sweeping assembly  12  are separately controlled and suspended from a frame  18  by way of independent suspension systems.  FIG. 2  more particularly illustrates the sweeper system or assembly including hopper  44 . An embodiment of the present invention may be adapted to be utilized in such a prior art machine to couple a surface maintenance appliance, such as scrubbing assembly  14 , sweeping assembly  12 , and/or burnishing assembly  16  to machine  10 . It may be appreciated that other embodiments of the present invention may be utilized on other types or styles of machines to couple a surface maintenance appliance thereto. 
     Illustrated in  FIGS. 3-4  are various perspectives, views, and drawings of one embodiment of the sweeper and hopper system in accordance with the present invention. Referring to  FIG. 3 , a pair of arms  110 L and  110 R are pivotally mounted at one end to brush carriage member  120 . The other ends of arms  110 L and  110 R provide mounting members for attaching rotatable brushes  125 L and  125 R driven by independent drive motors  115 L and  115 R respectively.  FIG. 4  shows a hopper support member  122  secured to brush carriage member  120  for supporting hopper  600  at one end. The other end of hopper  600  is secured to carriage member  120  by way of a spring loaded pin arrangement  700  as more particularly illustrated in  FIG. 4  by way of a mating pin  710  secured to hopper  600 . Additional aspects of the particular sweeper and hopper system illustrated in the drawings are disclosed in Applicant&#39;s U.S. Pat. Application filed on May 29, 2002, entitled “Sweeping System with Removable Hopper,” Ser. No. 10/159,727 and claiming the benefit of priority of U.S. Provisional Patent Application Ser. No. 60/294,298. The entire disclosures of these two applications are incorporated by reference herein. 
     Brush carriage member  120  is pivotally attached to a bracket  75  intended to be mounted to a frame member  5  of the surface maintenance machine (not shown) by way of a 4-point overhead suspension system including support members or linkages  61 ,  62  and  64  as shown in  FIGS. 3 and 4 . Linkage  64  is pivotally mounted to slotted hole  76  of bracket  75  and is pivotally mounted at the opposite end to the hopper support member  122  by a pin extending through mounting bracket  70 . Slotted hole  76  is for adjustment of linkage  64 . Once linkage  64  is pivotally mounted at a point in slotted hole  76  there will not be translational movement along the slot. Linkage  61  is pivotally mounted to bracket  75  by pivot pin  71  extending through mounting bracket  65 . An upper end of linkage  61  is coupled to actuator linkage  72  through a “lost motion”device which permits actuator  80  to selectively engage linkage  61 . In the illustrated embodiment, lost motion device includes slot  81  and pin  83 . Alternative lost motion devices which permit selective engagement of linkage  61  to actuator  80  would be appreciated by those skilled in the relevant arts, including for example cable or chain devices. An opposite end of actuator linkage  72  is coupled to actuator  80 . The opposite end of linkage  61  is pivotally mounted to carriage  120  by a pin extending through mounting bracket  67 . Linkage  62  is pivotally mounted to bracket  75  by one end of pivot pin  71  which extends through mounting bracket  66  and  65 . The opposite end of linkage  62  is pivotally mounted to carriage  120  by a pin extending through mounting bracket  69 . 
     The overhead suspension system is intended to be responsive to surface obstacles to obviate damage which may be imparted to the sweeper system if a surface obstacle or surface irregularity is encountered by the hopper lip  610  as shown in FIG.  4 .  FIG. 4  illustrates the normal operative condition with brushes  125  in contact with a floor surface. In the normal operative condition, carriage  120  follows surface undulations and brushes  125  remain in contact with the floor surface. Upon contact with an obstacle, such as a floor joint, crack, etc., carriage  120  is biased into a response condition. The overhead suspension system  FIG. 5  illustrates a position of the overhead suspension system after response to the hopper lip  610  encountering an obstacle or surface irregularity. In an exemplary embodiment, hopper lip  610  flexes upon contacting an obstacle and tends to bias carriage  120  upwardly and rearwardly relative to the floor surface and direction of motion. As a result, the overhead suspension system lifts the hopper  600  and the brushes  125 L and  125 R together in a direction upwards and towards the back of the floor maintenance apparatus when the hopper lip  610  encounters an obstacle or surface irregularity. As the overhead suspension system lifts into the response position of  FIG. 5 , links  61 ,  62 , and  64  are retracted to the extent of the severity of an obstacle or surface irregularity. 
     By providing an overhead suspension system, the entire brush and hopper assembly (125, 600) can be automatically biased up and away from an obstacle when the hopper lip  610  comes into contact with the obstacle or surface irregularity, substantially preventing damage to the brushes  125 L and  125 R or hopper  600 . Because the suspension is overhead, the brushes  125 L and  125 R and hopper  600  can be lifted up into the boundaries of the frame of the floor maintenance apparatus. In addition, upon the obstacle being passed, the brush and hopper assembly is automatically lowered back into a normal operational position. 
       FIG. 6  illustrates the position of the hopper  600  and rotatable brushes  125 L and  125 R during transport. During a lift operation, actuator  80  is extended to engage link  61  which in turn causes links  61 ,  62  and  64  to rotate and translate the hopper  600  and rotatable brushes  125 L and  125 R up and clear of the ground surface. Once at a desire location, actuator  80  can be retracted to cause links  61 ,  62 , and  64  to rotate and in turn lower the hopper  600  and rotatable brushes  125 L and  125 R to the ground surface for subsequent operation. 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Summary:
A suspension device for coupling a surface maintenance appliance to a surface maintenance machine is disclosed. The suspension device includes a carriage member movably supported upon the maintenance machine through a plurality of linkages coupled to the carriage member. Together the plurality of linkages permit the carriage and surface maintenance appliance to follow undulations in the floor surface during operation of the surface maintenance machine. An actuator engages a lost motion device to lift the carriage member away from the ground surface. A variety of different floor surface maintenance appliances may be coupled to surface maintenance vehicles according to aspects of the present invention.