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CROSS REFERENCES TO RELATED APPLICATIONS  
         [0001]    None.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention is for a brush wear adjustment system and method, and in particular relates to a brush wear adjustment system for use in a street sweeping vehicle.  
           [0004]    2. Description of the Prior Art  
           [0005]    Rotary brushes utilized in street sweepers generally are mounted to the chassis of a truck or other suitable vehicle or structure. Normal wear and tear of a rotary brush during the sweeping mode results in worn rotary brush bristles the lengths of which are continually reduced due to abrasive qualities of the roadway with normal usage. The axle of the rotary brush is often secured between opposing pivot arms which gravitationally and automatically adjust in vertical fashion about pivot points to suitably contact the roadway and to compensate for the reduction in bristle length. As the bristle length is reduced, efficiency and effectiveness of the sweeping operation is increasingly degraded. Effective sweeping is predicated partially on the speed of the bristle tip, and is also predicted partially by the pressure of the bristles exerted downwardly to meet the roadway. A new rotary brush has long bristles which produces the highest bristle tip speed, and a well worn rotary brush has short bristles which produces a significantly slower and less effective bristle tip speed for the same rotary brush rate of rotation, thereby resulting in poorer and less effective sweeping. As the bristles wear, the rotary brush exhibits less control by gravitational downward force, thereby causing a lighter impingement with the roadway. Truck sweeper operators have lacked displays indicating brush wear which can be conveniently read in the control cab of a street sweeper. What is needed is a system which compensates for the degraded sweeping effectiveness and efficiency caused by continually shortening of the bristles of a rotary brush and which also displays brush wear. Such a system to provide consistent sweeping performance by increasing RPM of the rotary broom and/or adjusting the down pressure of the rotary broom is provided for by the present invention and method.  
         SUMMARY OF THE INVENTION  
         [0006]    The general purpose of the present invention is to provide a brush wear adjustment system and method.  
           [0007]    As used herein, a road sweeper is any kind of surface sweeper, including, among others, streets, roads, factory floors, and the like.  
           [0008]    According to one embodiment of the present invention, there is provided a brush wear adjustment system and method, including a mounting surface, an optional protective enclosure, a retainer bracket, a position sensor secured to the mounting surface, a lever arm secured to and extending from the position sensor, a return spring mounted between the optional protective enclosure or other suitable location on the sweeper truck chassis and the lever arm, a linkage secured on one end to the outboard end of the lever arm and on the other end to an adjustable clevis, a linkage bracket connected to the lower end of the adjustable clevis, an electro-hydraulic controller, and a hydraulic metering valve. The hydraulic valve connects to a hydraulic rotary brush motor. Although hydraulic devices are shown and described, other devices utilizing other methods of propulsion for speed control such as, but not limited to, electric motors, rheostats, voltage controls, electronic control and the like can be utilized without departing from the apparent scope hereof.  
           [0009]    The components of the invention are mounted to and about the chassis and other components of a sweeper truck or other such suitable vehicle or device. The position sensor and the connected lever arm are mounted to a mounting surface provided on a fixed portion of the sweeper chassis or optionally provided on an optional protective enclosure, and the linkage bracket secures to a pivoted support arm at a location between a pivot point and the corresponding rotary brush mount. The linkage attaches to and extends generally and substantially between the fixed portion of the sweeper chassis in communication with one of the pivoted support arms where displacement of the pivoted support arm is sensed by the position sensor via the interconnecting linkage. Information regarding the position of the pivoted support arm, and thus the length of the bristles, is sensed by the position sensor and sent by an interconnecting electrical cable to the electro-hydraulic controller which determines the proper and required rotary brush speed for efficient and effective sweeping by the ever shortening bristles. The position sensor also relays information to a readout display which can be located in the operating cab of the sweeper truck to indicate bristle wear. A hydraulic metering valve is actuated accordingly by the electro-hydraulic controller to increase the rotational speed of the hydraulic rotary brush motor to the required rotational speed. Aggressiveness of the sweep can be influenced by hydraulically operated cables attached to the pivoted support arms which support the rotary brush.  
           [0010]    In another embodiment of the invention, a manual system, may be employed where sensor  16  is eliminated, and the speed controller for controlling the rotation rate of the rotary brush is provided with a manual input setting determined by a simple visual inspection of the remaining brush bristles, which may be color coded, or in the alternative a window may be provided with indicia relative to the remaining brush bristle length. In turn, this setting may be provide as an input to a controller for controlling brush rotation rate or brush position or both in accordance with a predetermined relationship to the visual inspection of the brush bristle length.  
           [0011]    While the present invention has been particularly shown and described with reference to the accompanying figures, it will be understood, however, that other modifications thereto are of course possible, all of which are intended to be within the true spirit and scope of the present invention. Various changes in form and detail may be made therein without departing from the true spirit and scope of the invention as defined by the appended claims.  
           [0012]    More specifically, position sensor  16  is intended to provide an output signal indicative of remaining brush bristle length on the brush. Brush diameter or radius is, of course, related to brush bristle length. Likewise, brush weight is indicative of bristle length since as the bristles wear, the brush weight decreases. Thus, sensor  16  represents any type of sensor which may provide an output signal indicative of the quantity intended to be sensed, i.e., bristle length, for ultimately controlling either the rotation rate of the rotary brush and/or the pressure of the brush against the surface intended to be swept in order to achieve consistent sweeping performance of a road sweeper or the like. Accordingly, sensor  16  may be implemented by a wide array of sensors including proximity sensors, optical sensors, and weight sensors depending upon the selected control scheme in accordance with the principles of the present invention, all of which are intended to be within the spirit and scope of the present invention.  
           [0013]    Further, the most simplest form of the present invention is an open loop control system for setting the rotation rate of the rotary brush or brush position or both in response to the sensed value of the remaining bristles on the rotary brush. However, a closed loop control system may also be employed having more or less advantages. Further, the control system of the present invention may be complex employing an algorithmic relation of bristle length to the controlled parameter, i.e., brush rotation rate or position, or may simply be based on a selected or predetermined look up table relating the parameter intended to be controlled in response to the sensed value of the remaining bristles on the rotary brush, all of which are intended to be within the spirit and scope of the present invention. It should also be recognized that the brush wear system of the present invention may be implemented by a wide array of analog and digital techniques, including microprocessors, computers, software and firmware, and the like, and either being part of a sole system or part of a more complex controller having many more functions.  
           [0014]    Although depicted in the drawings is a particular rotary brush positioning system employing linkages, cables, hydraulic pumps, electro-hydraulic controllers, and hydraulic motors, and the like, others are of course possible. For example, the rotary brush system may be implement by electrical linear actuators or linear hydraulic actuators as opposed to pivotal arrangements shown in the drawings, and the like, all of which are intended to be within the true spirit and scope of the present invention.  
           [0015]    A significant aspect and feature of the present invention is a brush wear adjustment system which provides for consistent sweeping performance by adjustment of rotary brush speed and/or rotary brush down pressure.  
           [0016]    A significant aspect and feature of the present invention is a brush wear adjustment system which accommodates the constant and increasing shortening of bristles.  
           [0017]    Another significant aspect and feature of the present invention is a brush wear adjustment system which senses data relating to the rotating brush bristle length.  
           [0018]    Another significant aspect and feature of the present invention is a brush wear adjustment system which increases the rotational rate of a rotating brush to maintain the tip speed of a bristle.  
           [0019]    Yet another significant aspect and feature of the present invention is a brush wear adjustment system incorporating the use of a position sensor to determine vertical displacement of a rotary brush.  
           [0020]    A further significant aspect and feature of the present invention is a brush wear adjustment system incorporating the use of an electro-hydraulic controller to determine required rotary brush speed.  
           [0021]    A still further significant aspect and feature of the present invention is a brush wear adjustment system incorporating a metering valve controlled by an electro-hydraulic controller to vary the rotary brush speed.  
           [0022]    Yet another significant aspect and feature of the present invention is the use of the invention as a brush wear indicator where the wear or the amount of bristle remaining can be viewed on a swivelable readout display in the operator cab of a sweeper truck.  
           [0023]    Having thus described embodiments of the present invention and enumerated several significant aspects and features thereof, it is the principal object of the present invention to provide a brush wear adjustment system, and method for use in a road sweeper or other suitable device.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:  
         [0025]    [0025]FIG. 1 illustrates a brush wear adjustment system, the present invention, connected to components external to the invention;  
         [0026]    [0026]FIG. 2 illustrates an exploded view of the components of the invention mounted to a mounting surface;  
         [0027]    [0027]FIG. 3 illustrates an isometric view of the combined retainer bracket, bearing and lever arm in distanced alignment with the position sensor;  
         [0028]    [0028]FIG. 4 illustrates an exploded top view in partial cutaway of the relationship of the mounting surface, the optional protective enclosure, the position sensor, the retainer bracket, the bearing and the lever arm;  
         [0029]    [0029]FIG. 5 illustrates a top view in partial cutaway of the relationship of the mounting surface, the optional protective enclosure, the position sensor, the retainer bracket, the bearing and the lever arm;  
         [0030]    [0030]FIG. 6 illustrates in part the mode of operation of the invention in use where the brush wear adjustment system is incorporated into use with and mounted to a chassis and to a pivoted rotary brush support arm of a street sweeper; and,  
         [0031]    [0031]FIG. 7 illustrates in part the mode of operation of the invention in use where the brush wear adjustment system is incorporated into use with and mounted to a chassis and to a pivoted rotary brush support arm of a street sweeper.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    [0032]FIG. 1 illustrates a brush wear adjustment system  10 , the present invention, connected to components external to the invention the external components of which include a hydraulic reservoir and a hydraulic rotary brush motor, and a hydraulic pump. The invention mounts, in part, to a mounting surface  11  which can be almost any suitably located stable and planar surface of varying size, such as a nearby truck chassis member. The typically utilized mounting surface  11  could also be a separate planar structure, such as shown herein, and could also include an optional protective enclosure  12 , if desired. The mounting surface  11  serves as a direct or indirect mount for components including a retainer bracket  14 , a position sensor  16 , a lever arm  18 , and a return spring  20 . One end of a linkage  22  connects to the outwardly located end of the lever arm  18  and the other end of the linkage  22  communicatively connects to a linkage bracket  24  via an adjustable clevis  26 . The linkage  22  can be a rod, a chain, a cable or other suitable device which can connect the outwardly located end of the lever arm  18  to the linkage bracket  24  via the adjustable clevis  26 . An electrical cable  28  connects electrically between the position sensor  16  and an electro-hydraulic controller  30  to relay electrical positional information relating to the angular displacement of the lever arm  18  from a datum as measured by the position sensor  16 . Such electrical positional information is incorporated to control the speed of the rotary brush  76  and to provide information for a brush length readout display  33 .  
         [0033]    Electrical positional information is sent via the electrical cable  28  to the electro-hydraulic controller  30  which contains suitable circuitry or computational devices such as, but not limited to, a micro-computer, as well as other required controlling devices. The output of the electro-hydraulic controller  30  controls a metering valve  32  or other such suitable apparatus which under commands can variably deliver hydraulic fluid from a hydraulic reservoir and hydraulic pump under the correct pressure and suitable flow to the hydraulic rotary brush motor of a sweeper. In the alternative and in lieu of the metering valve  32 , the electro-hydraulic controller  30  could control a variable displacement hydraulic pump to power the hydraulic rotary brush motor; or, the electro-hydraulic controller  30  could directly control a variable speed rotary brush motor.  
         [0034]    Electrical positional information as provided by the position sensor  16  is sent via an electrical cable  29  to a computer  31  which drives the readout display  33  to provide bristle length information to either the driver or driver&#39;s assistant in the truck sweeper cab. The readout display  33  can be swivel mounted for viewing by the driver or driver&#39;s assistant.  
         [0035]    [0035]FIG. 2 illustrates an exploded view of the components of the invention mounted to a mounting surface  11 . The optional protective enclosure  12  having a plurality of planar sides  12   a - 12   n  can mount to one side of the mounting surface  11 . The mounting surface  11  is conveniently shown as a member which could be sized for mating with the optional protective enclosure  12 , but could be any suitable road sweeper panel or structure member extending beyond the optional protective enclosure. The position sensor  16  includes horizontally oriented mounting slots  34  and  36  centered about a rotationally positionable shaft  38  having a receptor slot  40 . The rotationally positionable shaft  38  extends slightly beyond the inwardly located planar surface  16   a  of the position sensor  16 . The position sensor  16  mounts to the back side of the mounting surface  11  and is mounted thereto where the extended end of the rotationally positionable shaft  38  accommodatingly aligns with a body hole  42  on the mounting surface  11 . Opposing arcuate slots  44  and  46  center about the body hole  42 , as well as aligning respectively with the mounting slots  34  and  36  of the position sensor  16 . Machine screws  48  and  50  extend through arcuate slots  44  and  46  and the mounting slots  34  and  36 , as well as slots  14   a  and  14   b  of the retainer bracket  14 , to engage lock nuts  52  and  54 . The entire position sensor  16  can be rotated about the rotationally positionable shaft  38  and be positionally rotated to the extent allowed by the relationship of the machine screws  48  and  50  engaging the arcuate slots  44  and  46  and the mounting slots  34  and  36 . Such rotational positioning allows for operational calibration of the brush wear system  10 . The lever arm  18  includes a shaft  56  fixedly extending through one end. The inwardly positioned end of the shaft  56  includes opposing flattened surfaces  56   a  and  56   b  to allow accommodation by the receptor slot  40  of the rotationally positionable shaft  38 . The opposing end of the lever arm  18  includes a spring engagement hole  60  and a cable connector engagement hole  62 . The return spring  20  connects between the lever arm spring engagement hole  60  and an anchoring hole  66  located on or near the mounting surface  11 . For purposes of example and demonstration, the anchoring hole  66  is shown on a bracket  67 . A bearing  68  is accommodated by and fits over the outwardly facing portion of the shaft  56  to serve as an interface between the shaft  56  and a bearing mount  70  located on the retainer bracket  14 . The retainer bracket  14  includes an outwardly located panel  14   c  upon which the bearing mount  70  is located, upper and lower offset panels  14   d  and  14   e  extending offsettingly at an angle from the upper and lower portions of the outwardly located panel  14   c , and inwardly located slot panels  14   f  and  14   g , including slots  14   a  and  14   b , extending vertically downwardly and upwardly from the offset panels  14   d  and  14   e , respectively. Offsetting the slots  14   a  and  14   b  allows free and clear access of the machine screws  48  and  50  to the arcuate slots  44  and  46  and the mounting slots  34  and  36  previously described.  
         [0036]    [0036]FIG. 3 is an isometric view of the combined retainer bracket  14 , bearing  68  and lever arm  18  in distanced alignment with the position sensor  16 . Shown in particular is the relationship of the lever arm  18  in close juxtaposition with the outwardly located panel  14   c  and being distanced therefrom, as shown in FIG. 5, by the planar portion  68   a  of the bearing  68  disposed therebetween.  
         [0037]    [0037]FIG. 4 is an exploded top view in partial cutaway of the relationship of the mounting surface  11 , the optional protective enclosure  12 , the position sensor  16 , the retainer bracket  14 , the bearing  68  and the lever arm  18 .  
         [0038]    [0038]FIG. 5 is a top view in partial cutaway of the relationship of the mounting surface  11 , the optional protective enclosure  12 , the position sensor  16 , the retainer bracket  14 , the bearing  68  and the lever arm  18 .  
       Mode of Operation  
       [0039]    [0039]FIGS. 6 and 7 illustrate the mode of operation of the invention in use where the brush wear adjustment system  10  is incorporated into use with and mounted to a chassis  72  and to a pivoted rotary brush support arm  74  of a street sweeper, where the rotary brush is in contact with a roadway  84 . A powered rotary brush  76  attaches to the rearward end of the pivoted rotary brush support arm  74  and to the rearward end of a corresponding similarly constructed and configured opposing pivoted rotary brush support arm (not shown), but referred to as pivoted rotary brush support arm  74   a . The powered rotary brush  76  and pivoted support arm  74  are supported by a pivot  78  and by a bracket  80  which is variably supported by a hydraulically operated positioning cable (not shown). Typically, positioning cables are attached to a torque tube which is influenced by a hydraulic cylinder to provide supportive lift for the pivoted rotary brush support arms  74  and  74   a  and the corresponding pivoted rotary brush support arm and for the rotary brush  76  to share the loading of the bristles  82 . Such an arrangement influences the amount of pressure applied between the bristles  82  of the rotary brush  76  and the roadway  84 . The aggressiveness, i.e., the amount of rotary brush down pressure of the sweep can be determined by the operator. The amount of pivoted rotary brush support arm and rotary brush support provided can be controlled by the operator to apply the correct amount of down pressure required for an individual sweeping job. Light debris, such as dust or dry leaves, would require light bristle pressure where a greater portion of the pivoted rotary brush support arm weight and rotary brush weight is provided by the hydraulically operated positioning cables where other heavier debris, such as wet leaves, dirt, small stones, gravel or the like, require heavy bristle pressure to achieve suitable sweeping where a lesser portion of the pivoted rotary brush support arm weight and rotary brush weight is provided by the hydraulically operated positioning cables. The linkage  22  at the end of the lever arm  18  connects to the pivoted support arm  74  to monitor the angular displacement of the pivoted support arm  74  where such displacement is determined by the length of the bristles  82 .  
         [0040]    [0040]FIG. 6 depicts a rotary brush  76  having full length bristles  82  yet unaffected by roadway abrasion and wear encountered during normal sweeping along the roadway  84 . Commencing with sweeping operations with bristles  82  being of full length, the pivoted support arm  74  is positioned as shown where the pivoted rotary brush support arm  74  is at or near the upwardmost angle of travel with respect to the full length of the bristles  82 . Accordingly, the lever arm  18  of the brush wear adjustment system  10  is positioned at or near the upwardmost angle of lever arm  18  travel and preferably the linkage  22  is tensioned slightly against the force of the return spring  20  to provide an accurate and responsive datum information for positional processing by the electro-hydraulic controller  30 . The appropriate and lower relative rotational speed of the rotary brush  76  having full length bristles  82  as sensed by the position sensor  16  and attached lever arm  18  is determined by the electro-hydraulic controller  30 . Such determination requires that the metering valve  32  or other such suitable device causes the hydraulic pressure from a hydraulic reservoir and hydraulic pump to be regulated or otherwise controlled to provide the proper and suitable rotational speed of the rotary brush  76 .  
         [0041]    [0041]FIG. 7 depicts a rotary brush  76  having shortened bristles, herein designated as shortened bristles  82   a , affected by roadway abrasion and wear encountered during normal and continued sweeping along the roadway  84 . During sweeping operations with the worn and shortened bristles  82   a , the pivoted support arm  74  being angularly displaced is positioned as shown where the pivoted rotary brush support arm  74  is at or near the lowermost angle of travel with respect to the shortened length of the bristles  82   a . Accordingly, the lever arm  18  of the brush wear adjustment system  10  is also positioned at or near the lowermost angle of lever arm  18  travel. Information regarding the shortened length bristles  82   a  of the rotary brush  76  as sensed by the position sensor  16  and attached lever arm  18  is delivered to the electro-hydraulic controller  30  and an appropriate rotary brush  76  speed is determined. Such determination requires that the metering valve  32  or other such suitable device causes the hydraulic pressure from a hydraulic reservoir and hydraulic pump to be accommodatingly regulated to provide the proper and increased and suitable rotational speed of the rotary brush  76 . Such increasing of the rotary brush  76  rotational speed and of the attached shortened bristles  82   a  increases the tip speed of the shortened bristles  82   a  to compensate for the degraded sweeping effectiveness and efficiency caused by continually shortening of the bristles  82  of the rotary brush  76  to promote consistent sweeping performances. During the sweeping operation and as the bristles  82  decrease in length, the speed of the rotary brush  76  is automatically increased at a suitable rate as sensed by the position sensor  16  which is rotated by angular displacement of the lever arm  18 . Positional information from the position indicator  16  is incorporated by the electro-hydraulic controller  30  at all times to produce a suitable rotary brush  76  rotational rate.  
         [0042]    Various modifications can be made to the present invention without departing from the apparent scope hereof.  
       Parts List  
       [0043]    [0043]                                                       10   brush wear adjustment system           11   mounting surface           12   optional protective enclosure           12a-n   planar sides           14   retainer bracket           14a-b   slots           14c   outwardly located panel           14d-e   offset panels           14f-g   slot panels           16   position sensor           16a   planar surface           18   lever arm           20   return spring           22   linkage           24   linkage bracket           26   adjustable clevis           28   electrical cable           29   electrical cable           30   electro-hydraulic controller           31   computer           32   metering valve           33   readout display           34   mounting slot           36   mounting slot           38   rotationally positionable shaft           40   receptor slot           42   body hole           44   arcuate slot           46   arcuate slot           48   machine screw           50   machine screw           52   lock nut           54   lock nut           56   shaft           56a-b   flattened surfaces           60   spring engagement hole           62   cable connector engagement hole           66   anchoring hole           67   bracket           68   bearing           68a   planar portion           70   bearing mount           72   chassis           74   pivoted support arm           76   rotary brush           78   pivot           80   bracket           82   bristles           82a   shortened bristles           84   roadway

Summary:
A brush wear adjustment system for use in a powered street sweeper to provide for consistent sweeping performance where wear of rotary brush bristles is constantly sensed and the rotational speed of the rotary brush is automatically increased to maintain a desired bristle tip speed to maintain desirable sweeping attributes. Rotary brush support arm angular displacement is monitored in order for an electro-hydraulic controller to influence rotational speed of the rotary brush and to provide a readout relative to bristle length.