Abstract:
An adjustable grader-spreader bar with a three-point hitch has a blade frame assembly comprised of a plurality of blade frames, each blade frame having a blade edge fastened at the bottom. The blade frames are slideably connected so that the blade frames have an adjustable overlap. Actuating devices, such as hydraulic rams, are used to extend or retract the blade frames, so that the width of the of the adjustable grader-spreader bar may either be increased or decreased as required for the particular application. Ground engaging skids are attached to each side of the blade frame assembly. The vertical position of each ground engaging skid may be adjusted to raise or lower each side of the adjustable grader-spreader bar. Actuating devices, such as electrical motors, are used to change the vertical position of the ground engaging skids.

Description:
BACKGROUND 
     The present invention generally relates to towable devices which are used to grade ground surfaces or spread various materials over the ground surface where it is desirable to obtain a particular finished grade of ground surface or to blend additives into the soil. Such grater-spreader devices are used for a variety of purposes, such as applying paving materials, grading land for construction, and preparing land for agricultural purposes. More particularly, the present invention relates to a grader-spreader adapted to being towed by a tractor having a three-point hitch, where the blades of the apparatus readily adjust to a desired width. An additional feature of the present invention is that the angle and elevation of the cutting blades with respect to the ground surface are readily adjustable, thus allowing the operator to obtain a particular finished grade or slope. 
     It has been long known that devices towable by tractor provide an efficient and economical means of grading a ground surface and for applying various materials to the ground surface. While self-propelled grading and spreading machinery may accomplish the same task as towable devices, self-propelled machines are expensive, require substantial maintenance, and are often complicated to operate. Because towable devices are propelled by an all-purpose tractor, the devices are relatively inexpensive, simple to operate, and require less maintenance than self-propelled grading and spreading devices. 
     It has also been a long recognized need that towable grader-spreaders should be adaptable to provide service in a variety of different working conditions. If a grader-spreader device is used in a large open field to prepare the ground surface for planting crops, the operator may desire to adjust the device to obtain a virtually flat surface. However, if the device is used to spread asphalt on a roadway, it is often desired to obtain a final surface with sufficient slope to allow rain and spilled materials to rapidly drain off of the roadway surface. 
     The invention described in U.S. Pat. No. 4,320,988, issued to Seal on Mar. 23, 1982, discloses a towable grader-spreader utilizing a plurality of cutting blades adjustable in depth and angular position. The patent discloses a device which utilizes a plurality of cutting blades which can function as grader blades or as a spreader. The blades of the invention are adjustable both in depth and in angular position, where the respective ends of the blades may be positioned at different cutting depths from each other so as to vary the angle of a cut on a surface. The blades of the invention are positioned by a hydraulic ram adjustment mechanism. The cutting blades are mounted between a pair of side runners. The width of the device is fixed because the side runners are fixedly attached to one another. 
     The grader-spreader of U.S. Pat. No. 5,191,943 issued to Minor et al. on Mar. 9, 1993, discloses a pair of transversely extending blades rigidly mounted between two side members. While the ends of the blades of the grader-spreader in the &#39;943 patent are vertically adjustable, the width of the device is fixed. 
     SUMMARY OF THE INVENTION 
     An adjustable grader-spreader is disclosed which may be towed by a tractor or other vehicle adaptable to a three-point hitch, where the operator, from the operator&#39;s seat on the tractor, may make various adjustments to the grader-spreader to accommodate the immediate needs presented by the working conditions. Unlike other prior art devices, the width of the grader-spreader may be either increased or decreased, depending upon the requirements of the particular job requirements. The elevation of the blade edges relative to the work surface may also be adjusted. The adjustments are made through hydraulic and/or electric actuating devices which are commonly known to those skilled in the art. 
     The grader-spreader disclosed herein includes a blade frame assembly which is configured from a plurality of blade frames with a blade edge fastened at the bottom of each blade frame. The blade frames are slideably connected to one another so that the blade frames have an adjustable overlap. Actuators are connected to the blade frames in such a manner that the operator may remotely change the total width of the grader-spreader from the operator&#39;s position in the towing vehicle. In one embodiment, ground engaging skids are attached to either side of the blade frame assembly. 
     In one embodiment of the grader-spreader, a plurality of front stabilizers and rear stabilizers connect adjacent blade frames, providing the means for slideably connecting the adjacent blade frames. One means of sliding adjacent blade frames with reference to one another is by the use of hydraulic actuating rams. In the preferred embodiment, the blade frame assembly is comprised of a left blade frame, a right blade frame, and a center blade frame. 
     Elevating means may be used for adjusting the vertical positions of the left and right ground engaging skids thereby adjusting the level and angle of the blade edges with respect to the ground surface. One means of raising or lowering the ground engaging skids is by an electrical motor operating a screw jack connected to each ground engaging skid. 
     In an alternative embodiment, the ground engaging skids may be replaced by wheels on each side of the grader-spreader. The wheels may be independently raised or lowered with respect to the blade frame assembly by the same type of actuating means used to raise or lower the ground engaging skids. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a isometric view of a particular embodiment of the grader-spreader bar illustrating its connection to a tractor with a three-point hitch. 
     FIG. 2 shows the grader-spreader bar adjusted to its minimum width. 
     FIG. 3 shows the grader-spreader bar adjusted to its maximum width. 
     FIG. 4 shows a rear view of the grader-spreader bar. 
     FIG. 5 shows a front view of the grader-spreader bar. 
     FIG. 6 shows a side view of the left side of the grader-spreader bar. 
     FIG. 7 shows a detailed view of the rear of the grader-spreader bar, with the ram cover removed, illustrating the positioning and mounting of the left and right actuating rams. 
     FIG. 8 shows a detailed view of an embodiment of the grader-spreader bar, showing a rear view of the right side of the invention. 
     FIG. 9 shows an alternative embodiment of the grader-spreader bar in which wheels are used instead of ground engaging skids. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring now specifically to the drawings, FIG. 1 shows the adjustable grader-spreader bar  10  attached to a conventional tractor  11  by a three-point hitch assembly  12 , by which the grader-spreader bar is supported, towed and lifted for easy transportation. When a particular grading or spreading operation is complete, the tractor operator may lift the entire grader-spreader bar  10  off of the ground surface with the three-point hitch assembly  12  and transports the grader-spreader bar as desired. In the description which follows, the terms left, right, front, and rear are all with respect to the direction of travel of the grader-spreader bar, as it is being towed by the tractor  11 . The term outside refers to the side facing away from the center of the grader-spreader bar and the term inside means facing towards the center of the grader-spreader bar. 
     The grader-spreader bar is generally comprised of a blade frame assembly  13 , left ground engaging skid  38 , right ground engaging skid  40 , and a three-point hitch assembly  12 . The blade frame assembly  13  is comprised of a plurality of blade frames, such as the left blade frame  14 , the right blade frame  16  and the center blade frame  18  of the preferred embodiment. Fastened to the bottom of each blade frame, are the blade edges, such as the left blade edge  24 , right blade edge  26  and the center blade edge  28  respectively attached to the left blade frame  14 , the right blade frame  16  and the center blade frame  18  of the preferred embodiment. 
     The blade frame assembly  13  is assembled so that the left blade frame  14  overlaps the left side of the center blade frame  18  and the right blade frame  16  overlaps the right side of the center blade frame. The blade frame assembly  13  is assembled so as to allow adjustment of the overlap between the various blade frame sections thereby allowing the overall width of the blade frame assembly to be either increased or decreased. Various structural members support and guide the blade frame assembly  13  so as to provide sufficient rigidity for operation, yet also allow the width of the blade frame assembly to be adjusted. Structural members supporting the blade frame assembly  13  include the left front stabilizer  20 , the right front stabilizer  22 , the upper left rear stabilizer  46 , the upper right rear stabilizer  48 , the lower left rear stabilizer  50 , the lower right rear stabilizer  52 , the stabilizer mount  21 , the front stabilizer guides  23 , and the rear stabilizer guides  47 . Additional support is provided by a left guide rail  74  attached to the top of the left blade frame  14 , which guide rail glides along the top edge of the left side of the center blade frame  18  as the left blade frame is extended or retracted. Likewise, a right guide rail  76  is attached to the top of the right blade frame  16 , which glides along the top edge of the right side of the center blade frame  18  as the right blade frame is extended or retracted. 
     In the preferred embodiment, the left front stabilizer  20 , the right front stabilizer  22 , the stabilizer mount  21  and the stabilizer guide  23  are constructed of square or rectangular steel stock. Also in the preferred embodiment, the upper left rear stabilizer  46 , the upper right rear stabilizer  48 , the lower left rear stabilizer  50 , the lower right rear stabilizer  52 , and the rear stabilizer guides  47  are constructed of round steel stock. Also in the preferred embodiment, the left guide rail  74  and the right guide rail  76  are constructed of steel angle iron. 
     As depicted in FIG. 5, the outside facing end of the left front stabilizer  20  is connected to a stabilizer mount  21  which is attached to the front facing side of the left blade frame  14 . The inside facing end of the the left front stabilizer  20  is inserted through a stabilizer guide  23  attached to the front facing side of the center blade frame  18  so as to allow the stabilizer to slide through the guide as the left blade frame  14  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the left blade frame  14  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     Likewise, the outside facing end of the right front stabilizer  22  is connected to a stabilizer mount  21  which is attached to the front facing side of the right blade frame  16 . The inside facing end of the right front stabilizer  22  is inserted through the stabilizer guide  23  attached to the front of the center blade frame  18  so as to allow the stabilizer to slide through the guide as the right blade frame  16  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the right blade frame  16  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     As depicted in FIG.  3  and FIG. 4, the outside facing end of the upper left rear stabilizer  46  is attached to the upper inside face of the left side support  31 . The inside facing end of the upper left rear stabilizer  46  is inserted through a rear stabilizer guide  47 , which is attached to the upper rear of the center blade frame  18  so as to allow the stabilizer to slide through the rear stabilizer guide as the left blade frame  14  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the left blade frame  14  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     Likewise, the outside facing end of the upper right rear stabilizer  48  is attached to the upper inside face of the right side support  33 . The inside facing end of the upper right rear stabilizer  48  is inserted through a rear stabilizer guide  47 , which is attached to the upper rear of the center blade frame  18  so as to allow the stabilizer to slide through the rear stabilizer guide as the right blade frame  16  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the right blade frame  16  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     The outside facing end of the lower left rear stabilizer  50  is attached to the lower inside face of the left side support  31 . The inside facing end of the lower left rear stabilizer  50  is inserted through a rear stabilizer guide  47 , which is attached to the bottom rear of the center blade frame  18  so as to allow the stabilizer to slide through the rear stabilizer guide as the left blade frame  14  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the left blade frame  14  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     Likewise, the outside facing end of the lower right rear stabilizer  52  is attached to the lower inside face of the right side support  33 . The inside facing end of the lower right rear stabilizer  52  is inserted through a rear stabilizer guide  47 , which is attached to the rear of the center blade frame  18  so as to allow the stabilizer to slide through the rear stabilizer guide as the right blade frame  16  is either retracted to decrease the width of the grader-spreader bar  10 , as depicted in FIG. 2, or the right blade frame  16  is extended to increase the width of the grader-spreader bar as depicted in FIG.  3 . 
     The left blade frame  14  is extended or retracted by actuating means, such as the left hydraulic actuating ram  54 . The cylinder portion of the left hydraulic actuating ram  54  is configured to be attached to the center blade frame  18  as depicted in FIG.  7 . The piston portion of the left hydraulic actuating ram  54  is attached to the inside face of the left side support  31 . As depicted in FIG. 3, hydraulic fluid is provided to the left hydraulic actuating ram  54  by hydraulic supply hoses  62 . A left two-way transfer valve  58  provides hydraulic fluid to the left hydraulic actuating ram  54  so as to either extend the piston of the ram and thus extend the left blade frame  14 , or to retract the piston of the ram, thus retracting the left blade frame. 
     Likewise, the right blade frame  16  is extended or retracted by actuating means, such as the right hydraulic actuating ram  56 . The cylinder portion of the right hydraulic actuating ram  56  is configured to be attached to the center blade frame  18 , as depicted in FIG.  7 . The piston portion of the right hydraulic actuating ram  56  is attached to the inside face of the right side support  33  as depicted in FIG.  3 . Hydraulic fluid is provided to the right hydraulic actuating ram  56  by hydraulic supply hoses  62 . A right two-way transfer valve  60  provides hydraulic fluid to the right hydraulic actuating ram  56  so as to either extend the piston of the ram and thus extend the right blade frame  16 , or to retract the piston of the ram, thus retracting the right blade frame. 
     The left hydraulic actuating ram  54  and the right hydraulic actuating ram  56  are protected by the ram cover  70 . FIG. 7 illustrates the mounting of the left hydraulic actuating ram  54  and the right hydraulic actuating ram  56 , with the ram cover  70  removed. 
     The grader-spreader bar is supported on the left side by the left ground engaging skid  38  and on the right side by the right ground engaging skid  40 . As depicted in FIG. 9, an alternative embodiment is to replace left ground engaging skid  38  with left wheel assemblies  39  and to replace right ground engaging skid  40  with right wheel assemblies  41 . 
     Left ground engaging skid  38  and right ground engaging skid  40  are respectively mounted to the bottoms of the left skid frame  30  and the right skid frame  32 . The skid frames may be adjusted vertically by sliding up or down on the left elevation guide  42  and the right elevation guide  44 , which are attached, respectively, to the left side support  31  and the right side support  33 . Skid frame supports  78  are attached to the inside face of the left skid frame  30 , overlapping left side support  31 . Likewise, skid frame supports are attached to the inside face of the right skid frame  32 , overlapping right side support  33 . Raising or lowering the skid frames may be accomplished by elevating means, such as by the left elevating motor  34  and the right elevating motor  36 , which respectively rotate the left screw jack  35  and the right screw jack  37 . The slope meter  72  is used to accurately adjust the ground engaging skids to obtain the desired grade. 
     When electrical motors are used for elevating means, the invention is equipped with an electrical junction box  64 , electrical motor leads  66 , and electrical lead supports  68 . The electrical lead supports  68  prevent the electrical leads  66  from becoming entangled in the moving components of the blade frame assembly  13 . 
     Inasmuch as the function of the left ground engaging skid  38  and the right ground engaging skid  40  is to provide low friction surfaces to support each side of the grader-spreader bar  10  as the invention is towed, alternative devices may be substituted for the skids. For example, as depicted in FIG. 9, left wheel assemblies  39  might be attached to left skid frame  30  and right wheel assemblies  41  might be attached to right skid frame  32 , replacing left ground engaging skid  38  and right ground engaging skid  40 . Among other uses, the embodiment with wheels might be used for asphalt grading and paving and would allow overlapping hot asphalt without any joints. As an alternative to this embodiment, wheels might be attached directly to the ground engaging skids. 
     Use of the adjustable grader-spreader bar is simple to those who are familiar with the operation of tractors and towing machinery with a three-point hitch. The hydraulic supply hoses  62  from the left transfer valve  58  and the right transfer valve  60  are connected to the tractor hydraulic system, allowing the operator to control the flow of hydraulic fluid to the left actuating ram  54  and the right actuating ram  56  and thereby adjust the width of the grader-spreader bar from the seat of the tractor  11 . Conventional electrical switches may be used to independently operate the left elevating motor  34  and the right elevating motor  36 , thus allowing the operator to control the blade elevation and blade angle from the seat of the tractor  11 . 
     The size, shape, location, or orientation of the various components may be changed as desired by those skilled in the art without departing from the spirit and scope of the invention. The function of one element may be performed by two, and vice versa. It is not necessary for all advantages to be present in a particular embodiment at the same time. Thus, the scope of the invention should not be limited by the specific structures disclosed.