Grading tools, systems, and methods

Abstract

The present subject matter relates to devices, systems, and methods for shaping complex contours using a grading tool that is pushed or pulled along the ground. The grading tool can include a ground-engaging blade comprising a leading edge having a substantially concave profile and a trailing edge having a substantially convex profile and a coupling element connected to the blade and configured to adjust an angle at which the blade contacts a ground surface.

What is claimed is: 
     
         1 . A grading tool comprising:
 a ground-engaging blade comprising a leading edge having a substantially concave profile and a trailing edge having a substantially convex profile; and   a coupling element connected to the blade and configured to adjust an angle at which the blade contacts a ground surface.   
     
     
         2 . The grading tool of  claim 1 , wherein the leading edge has a positive rake blade angle. 
     
     
         3 . The grading tool of  claim 1 , wherein the trailing edge has a negative rake blade angle. 
     
     
         4 . The grading tool of  claim 1 , wherein the coupling element is configured to tilt the blade about a horizontal axis that is substantially perpendicular to a centerline of the tool. 
     
     
         5 . The grading tool of  claim 1 , wherein the coupling element is configured to tilt the blade about a secondary axis that is substantially parallel to a centerline of the tool. 
     
     
         6 . The grading tool of  claim 5 , wherein the coupling element comprises a biasing element configured to dampen rotational loads applied to the blade about the secondary axis. 
     
     
         7 . The grading tool of  claim 1 , comprising a variable height device that includes an edge extension that is movable relative to the blade between a lowered position in which the edge extension is positioned in alignment with the leading edge and one or more raised position in which a gap is formed between the edge extension and the blade. 
     
     
         8 . A system for grading a ground surface, the system comprising:
 a grading tool comprising:
 a ground-engaging blade comprising a leading edge having a substantially concave profile and a trailing edge having a substantially convex profile; and 
 a coupling element connected to the blade and configured to adjust an angle at which the blade contacts a ground surface; and 
   a draft linkage assembly connected at a first end to the grading tool and at a second end to machine or vehicle;   wherein the draft linkage is configured to move the grading tool relative to the machine or vehicle.   
     
     
         9 . The system of  claim 8 , wherein the draft linkage comprises one or more hydraulically-movable arms. 
     
     
         10 . A method for grading a ground surface, the method comprising:
 positioning a grading tool at or near a ground surface to be graded, the grading tool comprising a ground-engaging blade comprising a leading edge having a substantially concave profile and a trailing edge having a substantially convex profile;   adjusting an angle of the blade with respect to the ground surface;   moving the blade with respect to the ground surface to produce a desired surface configuration.   
     
     
         11 . The method of  claim 10 , wherein positioning a grading tool at or near a ground surface to be graded comprises lifting or lowering the tool relative to the ground surface to adjust one or both of a height at which the blade is positioned over the ground surface or a downward pressure applied by the blade to the ground surface. 
     
     
         12 . The method of  claim 10 , wherein adjusting an angle of the blade with respect to the ground surface comprises tilting the blade about a horizontal axis that is substantially perpendicular to a centerline of the tool. 
     
     
         13 . The method of  claim 12 , wherein adjusting an angle of the blade with respect to the ground surface comprises positioning the leading edge of the blade at or near the ground surface; and
 wherein moving the blade with respect to the ground surface comprises gathering material from the ground surface in front of the leading edge.   
     
     
         14 . The method of  claim 13 , wherein gathering material from the ground surface in front of the leading edge comprises stopping gathering when a carrying capacity of the blade is reached. 
     
     
         15 . The method of  claim 14 , comprising moving an edge extension into alignment with the leading edge to increase the carrying capacity of the blade. 
     
     
         16 . The method of  claim 13 , wherein gathering material from the ground surface in front of the leading edge comprises gathering material in excess of a carrying capacity of the blade to cause a flow of material over a top of the blade. 
     
     
         17 . The method of  claim 12 , wherein adjusting an angle of the blade with respect to the ground surface comprises positioning the trailing edge of the blade nearer to the ground surface than the leading edge; and
 wherein moving the blade with respect to the ground surface comprises spreading material along the ground surface beneath the blade.   
     
     
         18 . The method of  claim 10 , wherein adjusting an angle of the blade with respect to the ground surface comprises tilting the blade about a secondary axis that is substantially parallel to a centerline of the tool.