Patent Publication Number: US-2005127741-A1

Title: Grinder vehicle for removing traffic markings

Description:
FIELD OF THE INVENTION  
      This invention relates to a grinder vehicle for removing traffic markings from an underlying roadway surface, and more particularly, to such a grinder vehicle having a self propelled drive unit with an engine that drives both the drive unit and a grinder head assembly.  
     BACKGROUND OF THE INVENTION  
      Roadways are often constructed from concrete or asphalt materials. Traffic markings, such as painted markings, painted lines, epoxy markings, thermoplastic lines, and tape lines, among other markings, are often applied to roadway surfaces to direct traffic. Occasionally, it becomes necessary to remove traffic markings from roadway surfaces.  
      Traditionally, traffic line removal has been accomplished by manually propelled grinders. Often these grinders remove the traffic markings at an undesirably slow rate and leave undesirably large indentations in the roadway surface in the areas where the traffic lines have been removed.  
      Some traffic line removal units have a grinder that is connected to a separate, independently driven self-propelled drive unit. However, although the self-propelled drive unit facilitates movement of the grinder, the motor in the grinder remains relatively small, causing the traffic marking removal rate of the traffic line removal unit to remain undesirably slow. Accordingly a need exists for an improved grinder for traffic lines from an underlying roadway surface.  
     SUMMARY OF THE INVENTION  
      In one embodiment, the present invention is a grinder vehicle for removing traffic markings from an underlying roadway surface. The grinder vehicle includes a drive unit having a frame assembly supported by a plurality of wheels and a drive unit engine that drives at least one of the plurality of wheels. A drive shaft is connected to the drive unit engine. A grinder head assembly is connected to the frame assembly of the drive unit and is driven by the drive shaft of the drive unit engine. The grinder head assembly includes a plurality of grinder heads for removing the traffic markings from the underlying roadway surface.  
      In another embodiment, the present invention is a grinder vehicle for removing traffic markings from an underlying roadway surface. The grinder vehicle includes a drive unit having a frame assembly supported by a plurality of wheels and a drive unit engine that drives at least one of the plurality of wheels. A drive shaft is connected to the drive unit engine. A grinder head assembly is connected to the frame assembly of the drive unit and includes a main shaft that is driven by the drive shaft of the drive unit engine. A plurality of grinder heads for removing the traffic markings from the underlying roadway surface is mounted to and rotatable by the main shaft of the grinder head assembly. A downward pressure adjuster is connected to the grinder head assembly for varying a downward pressure that each grinder head applies to the traffic markings and the underlying roadway surface.  
      In yet another embodiment, the present invention is a grinder vehicle for removing traffic markings from an underlying roadway surface. The grinder vehicle includes a drive unit having a frame assembly supported by a plurality of wheels and a drive unit engine that drives at least one of the plurality of wheels. A drive shaft is connected to the drive unit engine. A grinder head assembly is connected to the frame assembly of the drive unit and includes a main shaft that is driven by the drive shaft of the drive unit engine. A plurality of grinder heads for removing the traffic markings from the underlying roadway surface is mounted to and rotatable by the main shaft of the grinder head assembly. A hydraulic cylinder is connected to the grinder head assembly for varying a downward pressure that each grinder head applies to the traffic markings and the underlying roadway surface. A pivot adjuster is connected to the grinder head assembly for pivotally adjusting the position of the grinder head assembly with respect to the underlying roadway surface.  
      In still another embodiment, the present invention is a grinder for removing traffic markings from an underlying roadway surface that includes a grinder head assembly and a downward pressure adjuster. The grinder head assembly includes a plurality of grinder heads for removing the traffic markings from the underlying roadway surface. the downward pressure adjuster is connected to the grinder head assembly for varying a downward pressure that each grinder head applies to the traffic markings and the underlying roadway surface.  
      In another embodiment, the present invention is a grinder for removing traffic markings from an underlying roadway surface that includes a grinder head assembly and a pivot adjuster. The grinder head assembly includes a plurality of grinder heads for removing the traffic markings from the underlying roadway surface. The pivot adjuster is connected to the grinder head assembly for pivotally adjusting the position of the grinder head assembly with respect to the underlying roadway surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic perspective view of a grinder for removing traffic markings according to one embodiment of the invention having a drive unit and a grinder head assembly.  
       FIG. 2  is a schematic representation of a drive unit engine that drives both the drive unit and the grinder head assembly of the grinder for removing traffic markings of  FIG. 1 ;  
       FIG. 3  is a cutaway view of a frame assembly that houses the grinder head assembly of  FIG. 1 ;  
       FIG. 4  is a back view of the frame assembly of  FIG. 3 ;  
       FIG. 5  is a bottom view of the frame assembly of  FIG. 3 ;  
       FIG. 6  is an exploded view of a grinder head assembly for use in the grinder for removing traffic markings according to one embodiment of the invention;  
       FIG. 7  is schematic side view of a gear box showing the mating of a drive shaft of the drive unit and a pulley shaft that is connected to the grinder head assembly;  
       FIG. 8  is a front view of the frame assembly of  FIG. 3  showing a pivot adjuster attached thereto for pivotally adjusting the frame assembly; and  
       FIG. 9  is a side view of the frame assembly of  FIG. 8 . 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      As shown in  FIGS. 1-9 , embodiments of the present invention are directed to a grinder vehicle for removing traffic markings from an underlying roadway surface. The grinder vehicle includes a self propelled drive unit and a grinder head assembly. The drive unit includes an engine that drives both the drive unit and the grinder head assembly. The grinder head assembly contacts and grinds traffic markings to remove the markings from an underlying roadway surface.  
      The roadway surface may be any one of a variety of roadway surfaces, such as concrete, asphalt, or asphalt rubber, among other appropriate roadways. The traffic markings may include painted markings, painted lines, epoxy markings, thermoplastic lines, and tape lines, among other appropriate materials for use as a traffic marker.  
       FIG. 1  shows a grinder vehicle  10  for removing traffic markings from an underlying roadway surface according to one exemplary embodiment of the present invention. The grinder vehicle  10  includes a self propelled drive unit  12  having a cab portion  14  mounted to a frame assembly  24  of the drive unit  12  and supported by front and rear wheels  30  and  32 . The cab  14  includes a seat  16  for receiving an operator (not shown) and a steering mechanism  18  for rotating the front wheels  30  to direct the forward or reserve motion of the grinder vehicle  10 . In one embodiment, the steering mechanism  18  includes a typical steering wheel, disposed in close proximity to the seat  16  and connected to a power steering system.  
      The cab  14  also includes foot pedals. The foot pedals include a control pedal  20  and a brake pedal  22 . The control pedal  20  is connected to a hydrostatic drive of a transmission of the drive unit engine  26  (as shown in  FIG. 2 ). The brake pedal  22  is connected to a brake pad of each wheel  30  and  32 . Operation of the control and brake pedals  20  and  22  is discussed in detail below.  
      A housing assembly  42  that supports a grinder head assembly  40  (as shown in  FIG. 3 ) is mounted to and extends forwardly from the frame assembly  24  of the drive unit  12 . As shown in  FIG. 3 , the grinder head assembly  40  includes a plurality of grinder heads  44  for contacting and grinding traffic markings to remove the markings from an underlying roadway surface.  
      As described in detail below, the housing assembly  42  is moveable relative to the frame assembly  24  of the drive unit  12  to allow the grinder head assembly  40  to move between a grinding position, wherein the grinder heads  44  contact and grind the traffic markings, and a transporting position, wherein the grinder heads  44  are not in contact with the roadway surface.  
      As shown in  FIG. 2 , the drive unit engine  26  is connected to the wheels  30  and  32  of the vehicle. In one embodiment, the drive unit engine  26  drives the front wheels  30  of the drive unit  12  in a 2-wheel drive system. In another embodiment, the drive unit engine  26  drives both the front and the rear wheels  30  and  32  of the drive unit  12  in a 4-wheel drive system. Extending from the drive unit engine  26  is a drive shaft  34 . The drive shaft  34  enters a gear box  28  (as shown in  FIG. 3 ) and engages and drives a pulley system  36  (as shown in  FIG. 3 ), which in turn drives a main shaft  38  of the grinder head assembly  40  (as shown in  FIG. 3 .)  
      In one embodiment, the drive unit  12  is taken from a commercially available lawn mowing tractor, such as a John Deere® 1400 Series Mower, (hereinafter the John Deere® tractor.) The John Deere® tractor includes a drive unit similar to that described above having a cab portion mounted to a frame assembly and supported by front and rear wheels. A mower assembly is mounted to and extends forwardly from the cab portion, which includes a seat for receiving an operator. The mower assembly includes rotary blades for cutting a ground surface. The John Deere® tractor is driven by a drive unit engine having a drive shaft that extends from the drive unit engine to engage and rotatably drive the blades of the mower assembly.  
      The John Deere® tractor can be modified for use as the drive unit  12  in one embodiment of the present invention by disassembling the mower assembly from the frame assembly of the drive unit, mounting the housing assembly  42  of the grinder head assembly  40  to the frame assembly of the drive unit, and attaching the drive shaft  34  to the gear box  28  to drive the pulley system  36  and the grinder head assembly  40  attached thereto.  
      Other lawn mowing tractors that are suitable for modification and use as the drive unit  12  in exemplary embodiments of the present invention include lawn mowing tractors made commercially available by John Deere®, Jacobsen® and Toro® among other appropriate lawn mowing tractors made commercially available by other suitable manufactures and/or distributes. In addition, the drive unit in exemplary embodiments of the present invention may also be taken from other types of tractors and/or motored vehicles.  
       FIGS. 3-5  show a cut away view, a bottom view and a back view, respectively, of the housing assembly  42  of the grinder head assembly  40 . As shown, the gear box  28  is mounted to the housing assembly  42 . The gear box  28  houses the pulley system  36 . The pulley system  36  includes a pulley shaft  47  connected to a belt  48  that drives the main shaft  38  of the grinder head assembly  40 .  
      The gear box  28  includes an opening  46  that receives the drive shaft  34  of the drive unit engine  26 . As shown in  FIG. 7 , the drive shaft  34  has a gear head  49  that engages a gear head  51  of the pulley shaft  47  to transfer a rotation of the drive shaft  34  to the pulley shaft  47 . In the depicted embodiment, the gear heads  49  and  51  are oriented at a 45 degree angle with respect to each other and the diameter and teeth of the gear heads  49  and  51  have a one to one ratio. Preferably, compressible bushings, such as rubber bushings are mounted between the gear box  28  and the housing assembly  42  to reduce vibrations.  
      A shroud  60  is also mounted to the housing assembly  42 . The shroud  60  houses the grinder heads  44  of the grinder head assembly  40 . The grinder head assembly  40  includes a plurality of mounting shafts  52 . Each mounting shaft  52  extends laterally from the main shaft  38  of the grinder head assembly  40 . Each grinder head  42  is rotatably mounted about a perimeter of its corresponding mounting shaft  52 . As such, a rotation of the main shaft  38  of the grinder head assembly  40  causes each grinder head  44  to rotate both about the main shaft  38  of the grinder head assembly  40 , as shown by arrow  56 , and about its corresponding mounting shaft  52 , as shown for example by arrow  54 .  
      Each grinder head  44  includes a wheel  55  having a plurality of bits or teeth  58  extending peripherally about an outer perimeter thereof to contact and grind a traffic marking to remove the marking from an underlying roadway surface. In one embodiment, each bit  58  is composed of a tungsten carbide material. The bits  58  contact and grind the traffic markings, while minimizing the grinding of the underlying roadway surface. As shown in  FIGS. 3 and 4 , the shroud  60  includes a hinged portion  62  that pivots about a hinge  64  to allow for easy access and/or maintenance to the grinder head assembly  40 .  
      In one embodiment, the grinder head assembly  40  is a Rotary Cutter Head Assembly as shown in  FIG. 6 , which is commercially available from EDCO® (Equipment Development Company.) Each Rotary Cutter Head Assembly includes a hub  120 . The hub  120  includes a plurality of side openings  122  which each receive a portion of a corresponding one of the plurality of mounting shafts  52 . Each mounting shaft  52  is mounted to the hub  120  by a pin  124 . Each mounting shaft  52 , in turn, receives a grinder head  44 . Each grinder head  44  is mounted on a smooth surfaced portion of the mounting shaft  52  so that the grinder head  44  is rotatable about the mounting shaft  52 . Fasteners threadably engage a threaded portion  128  of the mounting shaft  52  to secure the grinder head  44  to the mounting shaft  52 . Washers  131  may be mounted adjacent to the grinder heads  44  for protection.  
      A base plate  130  connects the hub  120  to the main shaft  38  of the grinder head assembly  40  so that the hub  120  (and hence each grinder head  44 ) rotates when the main shaft  38  rotates. The main shaft includes a laterally extending mounting plate  135 . The mounting plate  135  includes openings  138  that are aligned with corresponding openings  132  and  136  in the hub  120  and the base plate  130 . Fasteners  134  extend through the openings in the base plate  120 , the hub  120  and the mounting plate  135  of the main shaft  38  and engage nuts  140  to secure the hub  120  to the main shaft  38 . An inner bushing  142  (such as a rubber bushing) and an outer bushing  144  (such as rubber bushings) are disposed in surrounding relation to the fasteners  134  to reduce vibrations. Each grinder head  44  includes a plurality of bits  58 , such as tungsten carbide bits. Preferably each grinder head  44  includes either 24 bits (part number TR3-24) or 48 bits (part number TR3-48.)  
      Other grinder head assemblies and/or grinder heads that are suitable for use in exemplary embodiments of the present invention include grinder head assemblies and/or grinder heads made commercially available by EDCO® or Smith Manufacturing Company®, among other suitable manufactures and/or distributors.  
      In one embodiment, the drive shaft  34  is electrically connected to a clutch and is only activated when the clutch is activated. In the embodiment of  FIG. 1 , the clutch is activated by a toggle switch  73  having on and off positions. The clutch switch  73  is located in cab  14  of the drive unit  12  in close proximity to the seat  16 , such as on a column  74  of the steering mechanism  18 . In one embodiment, the clutch is an electric magnet clutch.  
      The rotational speed of the drive unit engine  26  (and hence the rotational speeds of the drive shaft  34 , the pulley shaft  47 , the pulley belt  48 , the main shaft  38  of the grinder head assembly  40  and each grinder head  44 ) is variable and controlled by varying the position of a control lever  70  disposed in the cab  14  of the drive unit  12  in close proximity to the seat  16  (as shown in  FIG. 1 ). In one embodiment, the more the control lever  70  is moved from an idle position, the faster the rotational speed of the drive unit engine  26 .  
      As shown, in  FIGS. 1, 8  and  9 , a support bar  80  is mounted to the frame assembly  24  of the drive unit  12 , such as by mounting plates  82  and fasteners  81  and/or welding. The support bar  80  is rotatably mounted to the mounting plates  82 . The housing assembly  42 , in turn, is mounted to the support bar  80 . In the embodiment of  FIG. 8 , the support bar  80  includes arms  83  that are mounted to a connecting rod  84  and the housing assembly  42  includes arms  85  that are similarly mounted to the connecting rod  84 , such that a movement of the support bar  80  causes a corresponding movement of the housing assembly  42 .  
      As shown in  FIGS. 1, 8  and  9 , a pivot adjuster  66  is connected to the housing assembly  42  to pivotally adjust the housing assembly  42  and hence the grinder head assembly  40  mounted therein. Pivotally adjusting the grinder head assembly  40  facilitates the grinding of traffic markings from a crowned, angled or otherwise irregular roadway surface.  
      The pivot adjuster  66  includes a threaded rod  68  having a handle  90  that is disposed in close proximity to the seat  16  of the cab  14  of the drive unit  12 . The handle  90  is used to rotate the threaded rod  68  as shown by arrow  91 . Rotation of the handle  90  causes the housing assembly  42  to pivot about an axis  95  as shown by arrow  96  and described in more detail below.  
      The pivot adjuster  66  is connected to both the support bar  80  and the housing assembly  42 . The pivot adjuster  66  is connected to a collar  87  that, in turn, is connected to the support bar  80  through a pivot arm  88 , which is pivotally connected to the support bar  80 . The collar  87  is held to the threaded rod  68  by fasteners  97 . The collar  87  has an internal bore that prevents the collar  87  from moving relative to the threaded rod  68  when the handle  90  is rotated.  
      The pivot adjuster  66  is also connected to the housing assembly  42 . The pivot adjuster  66  is connected to the housing assembly  42  by an protruding arm  86  of the housing assembly  42 . The arm  86  has internal threads that threadably engage the threads of the threaded rod  68 , such that rotation of the handle  90  causes a corresponding movement of the arm  86  along the threaded rod  68 . Thus, rotation of the handle  90  causes a relative movement between the protruding arm  86  of the housing assembly  42  and the collar  87  of the support bar  80 . This movement, along with the non-rigid connection of arms  83  and  85 , respectively, to the connecting rod  85 , which connects the support bar  80  to the housing assembly  42 , allows the housing assembly  42  to pivot about the axis  95  as shown by the arrow  96 .  
      As shown in  FIG. 9 , also connected to the support bar  80  is a hydraulic cylinder  100 . The hydraulic cylinder  100  has a shaft portion  101  that is moveable relative to a body portion  103  by the action of hydraulic fluids. The hydraulic cylinder  100  is rigidly mounted to the frame assembly  24  of the drive unit  12 , such as by one or more fasteners  104  and/or welding. The hydraulic cylinder  100  is also rigidly mounted to a mounting plate  102  that extends from the support bar  80 .  
      Movement of the shaft  101  of the hydraulic cylinder  100  relative to the body of the hydraulic cylinder  100  causes the mounting plate  102  to rotate the support bar  80  as shown by arrow  112 . This, in turn, causes the connecting rod  84  and the housing assembly  42  of the grinder head assembly  40  to corresponding rotate as shown by arrow  112 . By varying the force of the hydraulic cylinder  100  exerted on the mounting plate of the support bar  80  the downward pressure, as indicated by arrow  114 , that the grinder heads  44  apply to the traffic markings of an underlying roadway surface  110  is varied.  
      In one embodiment, hoses are connected to the hydraulic cylinder  100  to add or remove hydraulic fluid from the hydraulic cylinder  100 . The hoses are connected to a hydraulic control lever  71 , which is located in close proximity to the seat  16  in the cab  14  of the drive unit  12 . The hydraulic control lever  71  actuates valves connected to the hydraulic fluid hoses to control the amount of hydraulic fluid that is distributed to or removed from the hydraulic cylinder  100 . The hydraulic control lever  71  has a neutral position where the grinder heads  44  are not in contact with the surface to be grinded  110 . Moving the hydraulic control lever  71  away from the neutral position causes the hydraulic cylinder  100  to move the grinder heads  44  into contact with the surface  110  to be grinded. Each movement of the hydraulic control lever  71  away from the neutral position increases the downward pressure that the grinder heads  44  apply to the surface  110  to be grinded.  
      In one embodiment, the hydraulic cylinder  100  can exert up to approximately 1600 psi (pounds per square inch) of pressure. As a result, by movement of the hydraulic control lever  71 , the down pressure that the grinder heads  44  apply to the surface  110  to be grinded can vary from zero to approximately 1600 psi.  
      To drive the grinder vehicle  10  in either the forward or reverse directions, the control pedal  20  must be depressed and the control lever  70  must be moved from an idle position. Depressing the control pedal  20  activates the hydrostatic drive of the transmission of the drive unit engine  26 . The control pedal  20  controls the amount of fuel that is distributed to the drive unit engine  26 . Thus, the more the control lever  70  is moved from an idle position, the more fuel that is distributed to the drive unit engine  26  and the faster the rotational speed of the drive unit engine  26 . To drive the grinder vehicle  10  in a forward direction, a top portion of the control pedal is depressed. To drive the grinder vehicle  10  in a reverse direction, a bottom portion of the control pedal is depressed.  
      When the grinder vehicle  10  is being driven, the grinder heads  44  can either be activated to grind a surface or deactivated by toggling the clutch switch  73 , which controls the drive shaft  34  of the drive unit engine  26 . The drive shaft  34  drives the grinder heads  44  as described above. An advantage of having a single drive unit engine  26  that drives both the drive unit  12  and the grinder head assembly  40  and having the grinder head assembly  40  activated by the actuation of a clutch is that the drive unit  12  can be driven to a desired location while the grinder head assembly  40  remains in a inactivated state. The grinder head assembly  40  can then be activated only when it is desired to grind a surface, increasing the safety of the grinder vehicle  10 .  
      A grinding operation can also be performed when the grinder vehicle  10  is stationary. In order to perform such an operation, the clutch switch  73  is turned to the on position, thus activating the drive shaft  34  of the drive unit engine  26 , and the control lever  70  is moved from an idle position, while the control pedal  20  is not depressed. Thus, the grinder head assembly  40  is activated but the hydrostatic drive of the transmission of the drive unit engine  26  is not activated. As such, the grinder head assembly  40  can grind a surface while the grinder vehicle  10  is stationary. As discussed above, the more the control lever  70  is moved from an idle position, the more fuel that is distributed to the drive unit engine  26  and the faster the rotational speed of the drive unit engine  26  (and hence the drive shaft  34  and the grinder head assembly  40  driven thereby.) In one embodiment, the drive unit engine  26  is a twenty four Horsepower, three cylinder, liquid cooled diesel engine. Such an engine is much larger than engines used in traffic marking removers of the prior art. Using a twenty four horsepower engine allows the drive unit  12  to drive the grinder vehicle  10  to a speed in a range of approximately zero to twelve mph (miles per hour) in the forward direction and to a speed in a range of approximately zero to five mph (miles per hour) in the reverse direction.  
      Since the control lever  70  controls the speed of rotation of the drive unit engine  26  and the engine  26  drives the grinder heads  44  through the drive shaft  34 , the control lever  70  also controls the speed of rotation of the grinder heads  44 . Therefore, the speed of rotation of the grinder heads  44  is also variable. In one embodiment, the drive shaft  34  rotates each grinder head  44  at a speed in the range of approximately 200 rpm (revolutions per minute) to approximately 1600 rpm. Rotating the grinder heads  44  against the traffic markings of an underlying roadway surface at such high rotational speeds allows the grinder vehicle  10  to remove the traffic markings at a much faster rate than other grinders.  
      As shown in  FIG. 1 , a water tank  70  and a vacuum (not shown) are each attached to the cab  14  of the drive unit  12 . The water tank  70  and vacuum are each connected to a hose  72  and  74  having an opening in close proximity to the grinder head assembly  40 . Water from the water tank  70  may be applied in close proximity to the grinder head assembly  40  during a grinding operation to reduce dust from rising in the area above the roadway being grinded. The vacuum hose  74  may be placed in close proximity to the grinder head assembly  40  during a grinding operation to collect the dust that rises in the area above the roadway being grinded. The water tank  70  may be controlled by actuation of a valve and the vacuum may be activated by an electronic switch. The water valve and the electronic switch of the vacuum are each mounted in close proximity to the seat  16  in the cab  14  of the drive unit  12 . In addition, as shown, for example in  FIGS. 1, 3 ,  4  and  9 , a lower portion  65  of the shroud  60  is composed of a compressible material such as rubber. During a grinding operation, the lower portion  65  of the shroud  60  is compressed against the surface being grinded to help control the rising of dust from the surface being grinded.  
      The preceding description has been presented with reference to various embodiments of the invention. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, spirit and scope of this invention.