Abstract:
A tool system is provided for resisting abrasive wear of a ground-engaging tool of an agricultural implement during a crop production procedure. The tool system may include a tool for engaging an agricultural field while performing crop production procedure and that defines a main segment and a cutting segment having a working edge covered by a nanostructure coating. The cutting segment may include multiple wear zones with multiple working edges, respectively, covered by nanostructure coatings which may have different thicknesses.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Ser. No. 61/567,915 filed Dec. 7, 2011. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to farm implements and, more particularly, to tillage implements. 
         [0003]    One of the challenges constantly faced by farming and construction implement manufacturers is increasing the wear or usable life of working tools. Many of the soils in which such tools are used can be highly abrasive. In the context of farming implements, ground-engaging tools, which may include plow points, sweeps, shovels, knives, coulters, opener disks and other disks, and tines, depending on the type of implement, can experience substantial abrasive wear during use because the tools are continuously dragged through or across soil for long periods of time. Replacing tools that are abrasively worn out can be costly. As an example, for a tillage implement, as much as five percent of the implement&#39;s costs can be spent replacing tillage points each year. 
         [0004]    Addressing the issue of premature wear on such ground-engaging tools has typically involved two approaches. In the first approach, design efforts have been made to improve how the tools are pulled through soil. In other words, improving wear life of the tool by changing the shape or geometry of the tool. The other approach has been to focus on the physical makeup of the tool, such as hard-facing which typically includes building up thicknesses at high wear areas with welding to deposit material that typically includes granular hard materials encapsulated in the weldment, which typically provides irregular surfaces to such tools at the high wear areas. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to a tool system that includes an agricultural implement such as a tillage implement, planting implement, or seeding implement having one or more ground-engaging tools that are highly resistant to abrasive wear. The tools that are highly resistant to abrasive wear may include plow points, sweeps, shovels, knives, coulters, opener disks and other disks, and tines that may engage a field to perform a crop production procedure which may include residue management. The tools may have surfaces that are highly resistant to abrasive wear without introducing brittleness to the tools and which may operate at lower temperatures while being pulled through the soil of the field. 
         [0006]    According to one aspect of the invention, a tool system for resisting abrasive wear of a ground-engaging tool of an agricultural implement during a crop production procedure is provided that includes an agricultural implement towable behind a tractor in an agricultural field for performing a crop production procedure. The agricultural implement includes a frame, a tool support extending from the frame, and a tool arranged with respect to the tool support for engaging the field while performing crop production procedure. The tool may be made from a metallic parent material and may define a mounting portion for supporting the tool from the tool support and a working edge spaced from the mounting portion for contacting at least one of crop residue, weeds, and soil of the field while the tool engages the field. A nanostructure coating covers the working edge of the tool, the nanostructure coating may include nanostructures providing a greater hardness value at the working edge of the tool than at the mounting portion of the tool. This may provide a tool that is highly resistant to abrasive wear at high wear locations of the tool. 
         [0007]    According to another aspect of the invention, the nanostructure coating may define a first surface that is at least as smooth as a second surface defined at the mounting portion of the tool. This may provide a smooth hardened surface to portions of high-wear segments of agricultural tools that may provide a relatively low amount of friction between the tool and the soil that the tool is dragged through, which may lower the extent of friction-induced heating of the tool during use. 
         [0008]    The nanostructure coating may include a tungsten carbide material. The nanostructure coating may be applied using a CGDS (Cold Gas Dynamic Spray) process. This may allow high-wear segments of the tool to be coated with a wear-resistant coating that can be applied with a non-thermal procedure which may allow the coating to be applied to relatively thin materials such as opener disks without warping or otherwise thermally compromising the integrity of such thin materials. 
         [0009]    The tool may include a first wear zone and a second wear zone. The working edge and the nanostructure coating may define a first working edge and a first nanostructure coating, respectively, at the first wear zone. The second wear zone may define a second working edge and a second nanostructure coating overlying the second working edge. The second nanostructure coating may be thicker than the first nanostructure coating and may include more layers of a nanostructure material than the other one of the first and second nanostructure coatings. The first nanostructure coating may have at least two layers and the second nanostructure coating may have at least three layers. This may allow for a tool with hardened surfaces at portions of high-wear segments of agricultural tools without coating the entire tool and while providing an amount of coating that corresponds to the amount of wear at a particular area on the tool. 
         [0010]    According to another aspect of the invention, the nanostructure coatings may be applied to each of the first and second wear zones such that each of the first and second wear zones has an appearance that is visually distinguishable from the parent material of the tool. A worn condition that indicates abrasive removal of the nanostructure coating may be determined by visual inspection in which at least one of the first and second wear zones has an appearance that is visually indistinguishable from the parent material of the tool. A color of at least one of the first and second wear zones and a color of the parent material may be compared to determine wear of the nanostructure coatings. A common color of at least one of the first and second wear zones and the parent material may indicate the condition indicating abrasive removal of the nanostructure coating. This may allow for quickly determining whether the nanostructure coating is intact between uses of the agricultural implement. 
         [0011]    According to another aspect of the invention, the tool may be removed from the agricultural implement and the nanostructure coating may be reapplied to at least one of the first and second wear zones of the tool. The nanostructure coating may be reapplied to the cutting segment of the tool without applying the nanostructure coating to the main segment of the tool. This may allow for remanufacturing of the tools and may allow for a tool exchange program or remanufacture program. The tool may include a main segment and the mounting portion of the tool may be defined upon the main segment of the tool. The tool may include a cutting segment and the working edge may be defined upon the cutting segment of the tool. The cutting segment may be connected to the main segment so as to allow the cutting segment to be separated from the main segment for reapplication of the coating. This may allow for remanufacturing or an exchange program for the cutting segments of the tools. 
         [0012]    According to another aspect of the invention, single-walled carbon nanostructures may be incorporated as the coating or into the steel that is used to form the tool. The incorporation of the nanostructures may increase the strength of the tool and may allow for significant weight reduction, i.e., as much as an 80% reduction in weight compared to typical tools. According to another aspect of the invention, filamentous carbon molecules may be used to form the nanostructures and may be produced without metal catalysts so as to provide an inexpensive alternative to the typical hard-surfacing treatments of agricultural ground-engaging tools. According to another aspect of the invention, the nanostructure coating is applied at a lower temperature and is harder, thinner, and smoother than typical hard-surfacing treatments of agricultural ground-engaging tools. 
         [0013]    Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout and in which: 
           [0015]      FIG. 1  is a side elevation of a tractor pulling a schematic representation of a tool system in accordance with the present invention; 
           [0016]      FIG. 2  is a simplified isometric view of a carbon-based nanostructure in accordance with the present invention; 
           [0017]      FIG. 3  is a simplified isometric view of a variant of the carbon-based nanostructure of  FIG. 2 ; 
           [0018]      FIG. 4  is a simplified isometric view of another variant of the carbon-based nanostructure of  FIG. 2 ; 
           [0019]      FIG. 5  is a simplified isometric view of another variant of the carbon-based nanostructure of  FIG. 2 ; 
           [0020]      FIG. 6  is a simplified side elevation of a tool in accordance with the present invention; 
           [0021]      FIG. 7  is a simplified isometric view of another tool in accordance with the present invention; 
           [0022]      FIG. 8  is a cross-sectional view of various nanostructure coatings in accordance with the present invention; 
           [0023]      FIG. 9  is a simplified isometric view of another tool in accordance with the present invention; 
           [0024]      FIG. 10  is a simplified isometric view of a variant of the tool of  FIG. 9 ; and 
           [0025]      FIG. 11  is a flowchart of a procedure in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Referring to  FIG. 1 , a tool system  5  is shown that includes an agricultural implement  7  which is towable behind a tractor  9  and is schematically shown. Although the simplified schematic implement  7  resembles a disk harrow, the implement  7  may be a chisel plow, ripper, or other tillage piece of equipment, as well as a planter, a seeder, or other piece of equipment that has at least one ground-engaging tool, schematically represented in  FIG. 1  as tool  11 . The tool  11  is supported from a frame  13  of the implement  7  by a tool support  15  that is configured based on the particular type of tool  11 . As explained in greater detail elsewhere herein, the tool includes a nanostructure coating  17  that overlies parent material  19  at areas of the tool  11  that are susceptible to high abrasive wear. 
         [0027]    Referring to  FIGS. 2-5 , the nanostructure coating  17  includes nanostructure materials  21  that are more resistant to abrasive wear than the parent material  19  ( FIG. 1 ). The nanostructure materials  21  may include tungsten carbide arranged as filamentous carbon molecules that can be produced without metal catalysts and may include nanorods or nanotubes, shown schematically as nanotubes  23 A-C. The nanotubes  23  A-C are shown as carbon-based structures but it is understood that non-carbon nanostructures could be used.  FIGS. 2 and 3  show single-walled carbon nanotubes  23 A-B that include elongate bodies  25  with elongate openings  27  formed by arrays of carbonaceous molecules  29  that, in the illustrated examples, form diamond-mesh patterns. Nanotube  23 A of  FIG. 2  has a relatively smaller diameter and nanotube  23 B of  FIG. 3  has a relatively larger diameter, including diameters of their respective openings  27 . Referring to  FIG. 4 , the nanostructure material  21  is a composite of smaller and larger diameter nanotubes  23 A-B of  FIGS. 2 and 3 . The smaller diameter nanotube  23 A is arranged concentrically inside and extends beyond both ends of the larger diameter nanotube  23 B. Referring now to  FIG. 5 , the nanostructure material  21  includes nanotubes  23 C having metallic elements, such as metal atoms  31 , bonded to the body  25  of the nanotubes  23 C. These metal atoms  31  could be bonded to the nanotube body  25  using conventional chemical or mechanical bonding processes. 
         [0028]    Referring now to  FIG. 6 , the nanostructure coating  17  in this embodiment is applied to the tool  11  or a portion of the tool  11  by way of a non-thermal procedure  33 . The non-thermal procedure  33  of application of the nanostructure coating  17  is sufficiently low in temperature and changes in temperature of the tool  11  during application by such a small amount that the metallic parent material  19  of the tool  11  avoids undergoing temperature-induced characteristic changes. Such temperature-induced characteristic changes include warping and changes in annealing, tempering, or hardening of the parent material  19  while applying the nanostructure coating  17 . In one embodiment, the non-thermal procedure  33  includes application by way of a Cold Gas Dynamic Spray (CGDS) process. The CGDS process is a particle-coating process that accelerates gas to supersonic velocities through a De-Laval-type nozzle and carries the particles of the nanostructure materials  21  ( FIGS. 2-5 ) to the parent material  19  for bonding in which particles of the nanostructure materials  21  are accelerated above a critical velocity by a supersonic flow through momentum transfer. Critical velocity of particles of the nanostructure materials  21  corresponds to an impact velocity that the particles of the nanostructure materials  21  could have to allow for successful bounding to the parent material  19 . Regardless, the non-thermal procedure  33  allows for selective application of the nanostructure coating  17  to discrete portions of the tool  11 , as well as to control thickness of the nanostructure coating  17  at such portions of the tool  11 . 
         [0029]    Still referring to  FIG. 6 , the tool  11  is shown as an opener disk for use with a planter. The tool  11  defines a mounting portion  35  that engages the tool support  15  for supporting the tool  11  from the implement  7 . At least one cutting segment  37  is defined outwardly of the mounting portion  35 . The cutting segment  37  includes at least one wear zone  39  that may engage the soil during use and have at least one working edge  41  that may cut and be susceptible to dulling or other abrasive wear during use. 
         [0030]    Referring now to  FIG. 7 , the tool  11  is shown as a winged Tiger® point available from Case IH and which includes multiple cutting segments  37  which include at least one wear zone  39  and each having a nanostructure coating(s)  17 . A first cutting segment  37  is defined at a leading tip end  43  and the other cutting segments  37  are defined at a pair of wings  45  toward the mounting portion  35 . Referring now to  FIGS. 7 and 8 , different wear zones  39  may have coatings  17  of different thicknesses. The different thicknesses may be achieved by applying more of the nanostructure materials  21  ( FIG. 2-5 ) during the non-thermal procedure  33  ( FIG. 6 ) material in a single pass or, as shown in  FIG. 8 , by applying multiple and different numbers of layers  47  of the nanostructure materials  21  over the parent material  19 . The wear zone  39  facing upwardly at the leading tip end  43  may include at least two layers  47  of the nanostructure materials  21  as represented by the second wear zone  39  from the left-hand side in  FIG. 8 . The wear zone  39  facing downwardly at the leading tip end  43  may include at least three layers  47  of the nanostructure materials  21  as represented by the wear zone  39  at the far left-hand side in  FIG. 8 . The wear zones  39  at the wings  45  may include at least two layers  47  of the nanostructure materials  21 , optionally, a single layer  47  as represented by the wear zone  39  at the second to right-hand position of  FIG. 8 . The wear zones  39  of the wings  45  may be interconnected by a pair of segments of nanostructure coating(s)  17  that extend along the lines of intersection between the wings  45  and a main body  49  of the tool  11  and a segment of nanostructure coating(s)  17  that interconnects such pair of segments toward the mounting portion  35  of the tool  11 . Although described as discrete layers, in another embodiment, the nanostructure coating  17  may be defined by carbon or other nanostructure material  21  that is integrally formed with at least portions of the steel or other metallic material(s) used to form the parent material  19  of the tools, preferably arranged so that the carbon nanostructures are concentrated at the high-wear areas such as the working edge(s)  41  or wear zone(s)  39 . 
         [0031]    Referring now to  FIG. 9 , instead of tool  11  being a disk or Tiger® point as in  FIGS. 6 and 7 , respectively, the tool  11  is a sweep that is mounted to a shank-type to tool support  15  by way of a cooperating adapter  51  and pin  53 . This tool  11  defines an arrow-shaped body  55  with the cutting segment  37  defining a wear zone  39  having segments that converge toward each other and meet at a leading tip  57 . As shown at the bottom-positioned working edge  41 , the nanostructure coating(s)  17  may extend less than the entire length of the particular segment upon which it is arranged. Referring now to  FIG. 10 , like that of  FIG. 9 , the tool  11  of this embodiment is also a sweep. This tool  11  includes multiple cutting segments  37  that are individually connected to a main segment  59  of the tool  11 . The cutting segments  37  may be connected to the main segment  59  as replaceable parts by way of fasteners and/or suitable bonding agents. 
         [0032]    Referring now to  FIG. 11 , the tool system  5  ( FIG. 1 ) may be incorporated into a tool exchange program or remanufacture program, represented as program  61 . Generally, with such a program  61 , a tool  11  ( FIG. 1 ) would be used until the nanostructure coating  17  is worn and the parent material  19  of the tool  11  is exposed. Thereafter, the tool  11  or cutting segment  37  would be removed from the implement and sent to a suitable facility for reapplication of the nanostructure coating  17 . The remanufactured tool  11  could then be returned to the end-user for use or to a retailer to subsequently provide the remanufactured tool to the end-user. 
         [0033]    Still referring to  FIG. 11  and with reference to  FIG. 6 , at a suitable facility, the nanostructure coating  17  is applied to the tool  11  by way of the non-thermal procedure  33  ( FIG. 6 ) represented by block  63  of  FIG. 11 . As represented by block  65  of  FIG. 11 , the nanostructure coating  17  may be visually distinguishable from the parent material  19 . This may be done by leaving the parent material  19  in an at least somewhat unfinished state so that mill-scale or other minor surface irregularities are left on the parent material  19 . Spray application of the nanostructure coating  17  over the parent material  19  may remove at least some of the mill-scale and/or otherwise provide a relatively smoother surface at the nanostructure coating  17  than at, and which looks different than, the adjacent parent material  19 . Furthermore, the nanostructure materials  21  ( FIGS. 2-5 ) may have different colors than a color of the parent material  19  so as to further provide a visually distinguishable nanostructure coating  17  when compared to the parent material  19 . As represented by blocks  67  and  69 , respectively, the tool  11  is installed on the implement  7 , used, and then inspected for wear. As represented by block  71 , the inspection may be a purely visual one in which the user can readily determine whether the nanostructure coating  17  has been removed by looking at the tool  11 . As represented by block  73 , a common color of the parent material  19  and the wear zone  39  may be indicative of the worn condition, indicating abrasive removal of the nanostructure coating  17 . As represented by block  75 , after determining that the nanostructure coating  17  has been recently removed from the tool  11 , the tool  11  or the cutting segment(s)  37  is removed from the implement  7  or remainder of the tool  11 . As represented by block  77 , the tool  11  or cutting segments  37  are sent to a facility for reapplication of the nanostructure coating  17  by way of the non-thermal procedure  33  ( FIG. 6 ). As represented by block  79 , such reapplication provides another visually distinguishable nanostructure coating  17  from the parent material  19 . As represented by block  81 , the tool  11  is put back into use on an implement  7 . 
         [0034]    Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.