Patent Publication Number: US-6904979-B1

Title: Towable earth working apparatus having adjustable wheel height

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to the field of earth working equipment for landscaping, leveling, finish grading, cutting and spreading dirt, sand, gravel and the like. More particularly, the invention relates to such an apparatus capable of being towed by a light vehicle. 
   2. Description of the Prior Art 
   Ground surface grading devices for leveling and finish grading of rough terrain after preliminary smoothing by heavy equipment, such as a bulldozer or heavy tractor, have been available for many years. Grading equipment that can be shifted from one vehicle to another for greater operational flexibility is known and available commercially. Nevertheless, heavy-duty equipment, such as an earthmover or commercial tractor, must tow these devices. 
   Many potential operators of grading equipment, private individuals, businesses and local governments, do not have ready access to, or need heavy equipment to perform their work. But most operators usually have a vehicle such as a light truck, pickup truck, or small tractor that can be used for landscaping, ground leveling, finish grading, earth cutting, and for spreading dirt, sand, gravel and other such material at worksites, playing fields, gravel or dirt driveways and pathways, drainage culverts, and motor-cross tracks. 
   Most earth moving equipment is operated hydraulically via lines extending from the towing vehicle. Large equipment requires a reservoir of several gallons of hydraulic fluid for proper operation. Heavy-duty towing equipment may be able to provide such capacity, but vehicles normally employed by a private user cannot readily accommodate a large supplemental reservoir of hydraulic fluid. Instead, light vehicles must be modified to provide proper operation of the conventional towable earth working equipment, provided that the vehicles have the capacity to haul them. Such modifications increase the cost of the equipment and compromise operation of the vehicle. A more suitable towed apparatus would operate using hydraulic systems and other actuation equipment readily available to owners of light vehicles. 
   U.S. Pat. No. 5,289,880 describes a towable road grader for use behind a small vehicle, such as a pickup truck, the grader being either centered directly behind the towing vehicle or offset from center. A support frame secures a tending tool, a wheel frame pivots the rear towing wheels either toward or away from the support frame, and an attachment frame joins the other two frames to a hitch on the towing vehicle. The attachment frame keeps the support frame parallel to the plane of the underlying roadway surface as the support frame is raised or lowered. The attachment frame pivots upward when the tending tool is lowered to the roadway surface. As the wheels are raised and lowered, the cutting blade is raised and lowered. However, raising and lowering the wheels does not change the angular position of the blade relative to a horizontal plane or the ground surface. If the inclination of the blade were so changed, it would facilitate its engagement with the soil as ground conditions change and as the work requires. 
   U.S. Pat. No. 6,347,670 describes a device for modifying the ground surface by removing soil, moving the soil to a new location, and filling low areas. It includes a frame carried by wheels, a tongue mounted to the frame for attachment to a tractor, a cutting blade mounted on the frame, and a bucket pivotally mounted to the frame to receive soil cut by the blade. The wheels are pivotally mounted to the frame for movement about the back wall and floor of the bucket between a first position and second position. The position of the wheels is not adjustable between the extremities of travel between the first and second positions. 
   It would be desirable to have a device that is towable behind a light vehicle for moving over rugged ground or a smoother surface on which soil, sand, or gravel are to be moved or graded. It is desired to have an earth working apparatus that includes a grader supported on a frame by wheels that can be raised and lower over an adjustable range. Preferably, the grader would include a cutting blade that is easily raised and lowered as the wheels are raised and lowered, and its angular disposition adjustable relative to the horizontal. Also, it is preferable to have a grader that can be easily configured to make a number of different profiles for various working sites, such as a level field for sporting events or a contoured ditch for drainage. 
   SUMMARY OF THE INVENTION 
   An earth working apparatus according to this invention includes a trailer for attachment to a towing vehicle. The trailer includes a grader adjustably secured to a carriage, a wheel support assembly and a pivot attachment mechanism. The wheel support assembly rotatably supports laterally spaced wheels about a pivoting journal axis. A pivot attachment actuator and a wheel support actuator are connected to the frame via the attachment mechanism, which transmits actuator movement to the grader and wheel support assembly to raise and lower the grader and to adjust the angular disposition its blades. More specifically, the wheel support assembly pivots as a unit in opposite angular directions about the journal axis in response to the wheel support actuator, which raises and lowers the grader relative to the ground, and the angular disposition of the grader is adjusted in response to movement of the pivot attachment actuator. 
   The wheels, which provide ground support at the rear of the apparatus, are secured to the carriage frame by a wheel support assembly having arms extending from a jackshaft, which is supported on a journal. Pivoting movement of the wheels by simply changing the length of the wheel support actuator raises and lowers the wheels relative to the grader and changes the height of implements attached thereto, relative to a reference horizontal plane. 
   It is an object of this invention to provide an earth working apparatus that performs its work while being towed by a small vehicle such as a tractor or pickup truck. In addition to its ability to easily change the height of the grader, the inclination of the cutting blade and other implements on the grader are easily adjusted by simply changing the length of the pivot attachment actuator, such as a turnbuckle. 
   It is a further advantage that the angular position of the wheels, their height, the height of the cutting blade and its inclination are all adjusted and manipulated to achieve the optimum position by lengthening and shortening the pivot attachment actuator and the wheel support actuator linked by the pivot attachment mechanism. 
   The carriage frame is pivotally connected to the grader so that in operation the wheels extend rearward away from the grader. When the work is completed, the rear wheels are lowered and move forward, closer to and more directly under the grader, thereby transferring a significant portion of the apparatus weight to the wheels. When the tending tool has been lifted well off the ground surface, the apparatus is easily towed to another location. 
   It is another advantage that changes in the pivot attachment actuator&#39;s length are transmitted through the pivot attachment mechanism having an inherent mechanical advantage so that the inclination of the grader is adjusted with minimum effort. 
   Additionally, the apparatus is shock-mounted to the carriage frame in order to minimize damage from a rough roadway. Vibrations transmitted by the wheels to the wheel support assembly of the apparatus from irregular land surfaces are attenuated to the pivot attachment mechanism. The shock absorbing ability of the pivot attachment mechanism, in combination with the extenuated length of the trailer, dampens ground-induced vibrations and holds the grader at a relatively uniform elevation while passing over rough terrain. 
   Another aspect of the present invention includes interchangeable and adjustable rear blades attached to adjustment plates. Located at the perimeter of each adjustment plate are angularly spaced positioning holes, with which to adjust the angle of the rear blades. 
   Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     It is to be understood that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the instant invention, for which reference should be made to the claims appended hereto. Other features, objects and advantages of this invention will become clear from the following more detailed description made with reference to the drawings in which: 
       FIG. 1  is a perspective view of the apparatus having a trailer with a grader portion for attachment to a tow vehicle; 
       FIG. 2  is a plan view of the apparatus; 
       FIG. 3  is a side elevation view of the apparatus; 
       FIG. 4  is a side elevation view of a portion of an alternative pivot attachment mechanism; 
       FIG. 5  is a plan view of the grader portion; 
       FIG. 6  is a plan view of a portion of the carriage frame; 
       FIG. 7  is a perspective view of the apparatus with a modified carriage frame and the modified pivot attachment mechanism shown in  FIG. 4 ; and 
       FIG. 8  is a perspective view of the apparatus, without the implement frame support having a broom, as shown in  FIG. 7 , and the apparatus is shown attached to a small tractor by a three-way hitch. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings, an earth working apparatus  12  includes a trailer supporting a grader portion  14  having earth working implements. The trailer  15  includes a carriage frame  17  for supporting the grader portion on wheels  18 ,  19  and a pivot attachment mechanism  16  for connecting the entire apparatus to a vehicle that tows the apparatus. 
   As  FIGS. 1–3  show, the trailer  15  provides at its front end the pivot attachment mechanism  16  having a hitching assembly, which includes an attachment arm  20 , in the form of a hollow rectangular tube, and a shorter tube  22  fitted within and secured to the arm  20  by pins or bolts  24 . Tube  22  carries a pair of plates  26 ,  27 , each plate having a through hole  28  adapted to receive a trailer hitch pin, which is secured to the vehicle (not shown therein) after engaging the holes  28 . Of course, tube  22  can be easily removed and replaced, to receive a trailer towing ball, by pulling pins  24  and substituting it with another tube  22  having a ball hitch (not shown). The opposite end of the arm  20  is secured by triangular plates  30 ,  31  to a cross beam  32 , which extends laterally. Each lateral end of the beam  32  supports an end plate  34 ,  35 , which is attached by pins  36 ,  37  to the grader  14 . 
   Briefly jumping ahead to  FIG. 8 , the trailer  15  can easily be attached to a standard three-point hitch of a tractor, as an alternative to the trailer towing ball or hitch pin. An operator would simply remove the attachment arm  20 , by removing pins  36 ,  37 , and the engagement pin connecting the attachment arm  20  with the end of pivot attachment actuator  52 , and then attach the end plates  34 ,  35  and the unattached end of the pivot attachment actuator  52  to the tractor&#39;s three-point hitch as shown. 
   Returning now to  FIGS. 1–3 , pivot plate attachment block  40  is secured to the grader by a vertical post  42  and an inclined post  44  fixed to the grader; the block  40  being formed with holes  46 . A pivot attachment plate  48  of the pivot attachment mechanism  16  is adjustably supported on attachment block  40  for pivotable movement at a connection where a pin or bolt  50  engages one of the holes  46  in block  40  and a corresponding hole in pivot plate  48 . The pivot attachment mechanism  16  further includes a pivot attachment actuator  52 , such as a turnbuckle, secured at one end by a rod end connected to attachment arm  20 , and the pivot attachment actuator  52  is secured at its opposite end by a rod end connection and pin  51  to pivot plate  48 . Still further, a support frame linkage member  54  of the attachment mechanism  16  is attached at one of its ends to pivot plate  48  by a pin connection  56 . To complete the linkage, member  54  is attached at its opposite end to wheel support pivot plates  60 ,  61  by a pin connection  58 . The wheel support pivot plates  60 ,  61  are pivotably supported on a wheel support assembly  70  of the carriage frame  17 . 
   As briefly mentioned, it is preferred that the pivot attachment actuator  52  is a turnbuckle, however a hydraulic or pneumatic actuator can be used as an alternative. For purpose of this description, therefore, the pivot attachment actuator may be interchangeably referred to as turnbuckle  52 , but should not be so limited because of the alternatives. 
   In the preferred embodiment, each rod end of the turnbuckle  52  is formed with external screw threads. Further, the turnbuckle  52  includes a sleeve having internal threads at each end. One rod end is connected to the turnbuckle sleeve by a right-hand screw thread engagement connection; the other rod end is connected to the opposite end of the turnbuckle sleeve by a left-hand screw thread engagement connection. The turnbuckle  52  has a wheel handle  59  to facilitate rotation of the turnbuckle sleeve about its axis relative to the rod end connections, which are prevented from turning with the wheel handle  59 . The length of the turnbuckle  52  can be adjusted, lengthened and shortened, by rotating the turnbuckle sleeve about its longitudinal axis by the wheel handle  59  while holding against rotation the rod ends at each end of the turnbuckle. This lengthening and shortening movement of the turnbuckle causes the front end of the grader portion  14  to pivot about pins  36 ,  37  as the turnbuckle  52  pivots about pin  51  attached to the pivot plate  48 . As described in more detail below, the grader portion  14  further pivots about a pair of journals  122 , 123 . As a result, the angular inclination of the grader portion can be adjusted while maintaining the carriage frame  17  at an established height supported by the wheels  18 ,  19 . 
     FIG. 4  shows a slightly different embodiment of a portion of the pivot attachment mechanism. Therein, pivot plate  48 ′ has a triangular shape, which is suited for attachment at each corner to the turnbuckle  52 , block  40 , and linkage member  54 , respectively. Further, pivot plate  48 ′ carries a forked bracket  53  for supporting a hose that connects a source of hydraulic or pneumatic pressure carried on the vehicle to a wheel support actuator  116 , such as a hydraulic cylinder as described below, secured to the wheel support assembly  70  of the carriage frame  17 . Bracket  53  permits the hose to be draped loosely above the apparatus and to be supported there away from interference with the trailer or the grader and its implements. 
   Turning now to  FIG. 5 , the grader portion  14  has a right side rail  62  and a left side rail extending along the length of the grader, the side rails  62 ,  63  being inclined mutually and spaced apart laterally further at the rear than at the front of the grader for structural support. The front end of the grader portion  14  has a front cross member  64  and the back end of the grader has a back cross member  66  secured to the right and left side rails  62  and  63 . 
   Attached to the front cross member  64  below the side rails  62  and  63  is a V-shaped cutting blade  74  having an apex of the V-shape at the forward-most position of the grader portion  14  of the earth working apparatus  12 . The lower edge of the cutting blade is substantially in a plane, whose angular disposition with respect to a horizontal plane is changed by adjusting the length of the turnbuckle  52  as previously described. The angle at which the cutting blade contacts the soil, gravel, sand or other material being moved by the apparatus is changed to suit surface conditions and the type of work being performed. For example, the angle between the plane of the lower blade edge and a horizontal plane can be opened so that the forward-most edge  73  of the blade is higher than the trailing edge  75  and the back end of the blade  74  contacts the work material at a shallow upward angle, just barely making contact with the work material. The angle between the plane of the lower blade edge and a horizontal plane can be closed so that the forward-most edge  73  of the blade is lower than the trailing edge  75  and the blade enters the work material at a steeper angle to cut a path or culvert therethrough. 
   Attached to the back cross member  66  is a pair of rear blades  76  and  77 . One end of each rear blade  76 ,  77  is pivotally attached to the back cross member  66  by a rear blade hinge  80 , which is supported on the back cross member  66  by a plate and gusset. The axis of the hinge  80  is substantially vertical and perpendicular to the plane of the upper surface of the rear blades  76 ,  77 . 
   The angular position of the rear blades  76 ,  77  is adjustably secured about the axis of the hinge  80  by attachment of rear blade  76  to adjustment plate  86  and by attachment of rear blade  77  to adjustment plate  87 . Adjustment plate  86  is located below and attached to the right side rail  62 ; adjustment plate  87  is located below and attached to the left side rail  63 . Near the outermost perimeter of each adjustment plate  86 ,  87  are a plurality of positioning holes  78 ,  79 . Adjustment pin blocks  88 ,  89  are attached to rear blades  76  and  77 , respectively. Each adjustment pin block  88 ,  89  provides a gap between the respective rear blade and the corresponding mounting block permitting each rear blade to slide freely in its respective gap relative to the adjustment plate. Each adjustment pin block  88 ,  89  has a hole for registration and alignment with one of the positioning holes  78 ,  79  in the corresponding adjustment plate  86 ,  87 . Rear blade  76  may be secured at various angular positions by rotating the rear blade  76  about the pivoting hinge  80  and securing the rear blade  76  to adjustment plate  86  using a locking pin. In like fashion, the rear blade  77  may be secured at various angular positions by rotating the rear blade  77  about the pivoting hinge  80  and securing the rear blade  77  to the adjustment plate  87  also using a locking pin. Still further, the rear blades  76 ,  77  may be removed completely or changed from a pair of rear blades with a planer lower edge to a pair with a serrated lower edge (or vise-versa) by removing the hinge pin from the rear blade hinge  80  and the locking pins from the adjustment plates  86 ,  87 , and securing the pins once again when the chosen rear blades are in place as described above. 
   Located between rear blades  76  and  77  and the V-shaped cutting blade  74  is mounted a center cross-member  68  traversing right and left side rails  62  and  63 . Secured on the center cross-member  68  are adjustable, laterally-spaced scarifiers  94 , attached to member  68  by scarifier brackets  96 . The scarifiers extend below cross-member  68 , and they are removable from the grader by releasing attachment bolts and removing each scarifier from its bracket. 
   Turning now to  FIG. 6 , the carriage frame  17  for supporting the grader  12  on the wheels  18 ,  19  further includes a right side rail  102  and a left side rail  103 , these rails being located on the upper surface of the side rails  62 ,  63  of the grader, respectively, and secure thereto at bolted brackets  104 ,  105 . The back end of the rails  102 ,  103  supports a cross member  110 , which carries the wheel support assembly  70  having two laterally spaced plates  112 ,  113  extending upward above the upper surface of the cross member  110 . Each plate is formed with laterally directed, mutually aligned holes  114 ,  115  for connection to an end of a wheel support actuator  116 , such as a ratchet jack or hydraulic cylinder, described in more detail below. 
   The wheel support assembly  70  of the carriage frame  17  further includes a right side arm  118  and a left side arm  119 ; a pivot axle or cylindrical jack shaft  120  extending laterally between and secured to the front end of arms  118 ,  119 ; and an axle shaft  106  extending laterally between and supported on the arms  118 ,  119 . The trailer wheels  18 ,  19  are supported rotatably on the axle shaft  106 . At least a portion of the length of the outer surface of the jack shaft  120  is in the form of a circular cylinder. Jack shaft  120  is supported for rotation on journals  122 ,  123  located on and secured to the upper surface of the side rails  102 ,  103 . Preferably, each journal has a concave cylindrical surface, complementary to that of the jack shaft  120 , for supporting the grader  14  at least partially on the wheels  18 ,  19 , and additional support being provided by the towing vehicle by the attachment arm  20  of the attachment mechanism  16 . 
   The wheel support pivot plates  60 ,  61  are secured to the jack shaft  120  for movement with the jack shaft as it pivots on the journals  122 ,  123 . Pivot plates  60 ,  61  are mutually spaced laterally and formed with laterally directed, aligned holes for a pin connection at  58  to linkage member  54 , seen in  FIG. 3 . Pivot plates  60 ,  61  are formed also with aligned holes for a pin connection at  124  to the wheel support actuator  116 . The connections  58  and  124  are spaced angularly about the axis of the jack shaft  120 . 
   Located at the rear of the carriage frame is an implement frame support that includes a center post  130 , releasably secured to the carriage frame, and lateral posts  132 ,  133 , secured at release pins  134 ,  135  to the rails  102 ,  103 . The posts  130 ,  132 ,  133  are stabilized by a cross member  137 , and they support a laterally extending rail  136  having a cross section, preferably in the form of an angle. The rail  136  is supported in the position shown in  FIGS. 1–3  by using both pin connections  134  and  135  to support the posts  132 ,  133  vertically. However, the rail  136  can also be rotated and lowered by pivoting it on only one of the release pins  134 ,  135  and removing the other release pin. A broom having long, coarse bristles can be attached to the angle  136  such that the bristles contact the ground under the weight of the implement frame for sweeping a playing surface or spreading fine topsoil at a worksite before seeding. 
   In operation, the angular relation between an imaginary horizontal plane and the grader portion  14 , namely the lower edge of the V-shaped cutting blade  74  and rear blades  76  and  77 , can be changed by altering the length of the turnbuckle  52 . For example, if the turnbuckle  52  is lengthened by rotating its sleeve relative to the rod ends, grader portion  14  rotates counterclockwise on the pins  36 ,  37 , when viewed as in  FIG. 3 , as the corresponding end of the attachment arm  20  is lowered. This will lower the front end of the grader portion. The wheel support assembly holds the back end of the grader portion at its adjusted height, relative to the ground, since the back end of the grader portion  14  pivots with the carriage frame about the journals  122 ,  123  of the wheel support assembly  70 . As a result, the V-shaped nose  73  will be closed and pointed downward so that it will dig into the earth as the vehicle moves forward. Further, the lower edge of the rear blades  76 ,  77  will be positioned at the corresponding angle but relatively higher then the V-shaped nose  73 . With the V-shaped cutting blade  74  tilted forward and the rear blades  76  and  77  lifted entirely off the ground, a ditch can be cut using the apex  73  of the V-shaped cutting blade  74  as the operator travels forward. 
   If the turnbuckle  52  is shortened by rotating its sleeve relative to the rod end attachments, grader portion  14  rotates clockwise on pins  36 ,  37  as the attachment arm  20  is lifted. This then raises the front end of the grader portion. Again, the wheel support assembly holds the back end of the grader portion at its adjusted height, relative to the ground. The back end of the grader pivots with the carriage frame about the journals  122 ,  123  of the wheel support assembly  70 . As a result, the V-shaped nose  73  will be open and pointed upward, relatively higher then the rear blades  76 ,  77 . This allows the operator to lift the V-shaped cutting blade  74  entirely off the ground to use only the rear blades  76  and  77  for grading or back dragging. 
   Further, the height of the grader portion  14  can be changed relative to the ground by altering the length of the wheel support actuator  116 . The wheel support actuator  116  can be a manually operated by a ratchet jack (depicted in  FIGS. 1–3 ) or an automatically controlled hydraulic cylinder (depicted in  FIGS. 7–8 ) connected to the pivot plates  60 ,  61 . Viewing  FIG. 7 , a hydraulic cylinder  116 ′ is connected to a hydraulic pressure source to automatically manipulate the wheel support assembly  70  of the carriage frame  17 . By extending the wheel support actuator, the wheel support pivot plates  60 ,  61  and jack shaft  120  rotate counterclockwise, and raise the trailer wheels  18 ,  19  relative to the grader, thereby lowering the same. By shortening the wheel support actuator, pivot plates  60 ,  61  and jack shaft  120  rotate clockwise, thereby lowering the trailer wheels to raise the grader off of the ground. When the trailer wheels are raised and lowered, the angular inclination of the grader portion  14  does not change since turnbuckle  52  should be locked in its select extension. 
   In summary, the height and angular disposition of the cutting and rear blades can be raised and lowered relative to the horizontal plane over a wide range of adjustment by changing the length of the wheel support actuator  116 ,  116 ′ and the turnbuckle  52 . The grader can be quickly adjusted to accomplish the desired task, to the local topography of a worksite and to the amount of earth to be moved with each pass of the grader over the area. 
   Finally, the pivot attachment mechanism  16 , wheel support assembly  70  and extended length of the trailer  15  provide energy absorbing capability when the apparatus is moving, when the turnbuckle  52  and wheel support actuator  116  are set at adjusted lengths. More specifically, the play in the pivoting action of the pivot attachment plate  48  or  48 ′ about the pivot plate attachment block  40 , in combination with the play in the pivotability of the jack shaft  120  on journals  122 ,  123  of the wheel support assembly  70  and extended length of the trailer from the trailer hitch to the wheels  18 , 19 , dissipates sudden variations in work site elevation and vibrating energy transmitted by wheel movement. Therefore, if the pulling vehicle passes over a high area on the work site, the grader portion remains relatively level since the vertical movement of the vehicle is dissipated accordingly. 
   From the foregoing, it will be seen that this invention is well adapted to attain all the advantages set forth, together with other advantages. It will be understood that certain features and combinations are of utility and may be employed without reference to other features and combinations. It is to be understood that all the subject matter described here or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.