Earth working – Tool – standard or connection – Non-rectangular – symmetrical type
Reexamination Certificate
2001-07-30
2002-07-23
Novosad, Christopher J. (Department: 3671)
Earth working
Tool, standard or connection
Non-rectangular, symmetrical type
C172S730000, C172S770000
Reexamination Certificate
active
06422323
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an agricultural tillage system. More particularly, it relates to a tillage system that is capable of working the soil at a shallow depth with discs, and also providing some deep (“primary”) tillage at a second, deeper depth, and then leveling the field, all in a single pass, thereby conserving fuel and equipment operating time.
BACKGROUND OF THE INVENTION
Single-pass tillage implements providing both shallow and primary tillage in a single pass using discs and chisel points are disclosed in U.S. Pat. Nos. 4,245,706; 4,403,662; and 4,538,689. These machines, however, leave furrows and/or ridges in the soil after use. It has become desirable to leave the surface of the soil as level as possible after tilling in the Fall to reduce the amount of soil preparation necessary before planting the following Spring. U.S. Pat. No. 5,080,178 discloses a disc leveler for use with a tillage machine such as is disclosed in U.S. Pat. No. 4,403,662.
During the late 1970's, before the machine shown in U.S. Pat. No. 4,403,662 became available, primary tillage was accomplished principally with moldboard plows. The moldboard plow leaves large slabs and chunks of soil that tend to break down over the freeze and thaw cycles of Winter, but this tillage practice required substantial working of the soil in the Spring in order to level the field and prepare it for planting of the next crop. Moreover, moldboard plowing is not an effective remedy for soil erosion, and has a tendency to exacerbate erosion.
In recent years, farmers have been looking for ways to decrease soil and wind erosion. The use of a large disc assembly in front of a chisel plow on a parabolic shank accomplished these goals and also breaks up the hard plow pan (or “sole”) that is created at the particular depth at which the plow is set to operate, caused by repeated tillage at the same depth over the years. The parabolic shank and winged point of recent improved plows have reduced soil erosion, but this practice also may create large chunks of soil, and it usually requires substantial spring soil-working to prepare an adequate seedbed for planting.
During the 1970's, the cutter chisel was widely used. It consisted of a chisel plow with a row of coulters to cut the residue ahead of two rows of staggered shanks on thirty-inch centers. These shanks had a four-inch twisted point attached to them to perform the primary tillage. The tip of the point was at approximately a 45° angle to the horizontal, sloping downwardly and forwardly from the shank. The worked soil followed the curvature of the “C”-shaped shank that was attached to the chisel plow and was twisted in order to provide a moldboard-type turning action. A “C”-shaped shank, of the type described, is shown in U.S. Pat. No. 4,403,662.
For early cutter chisel plows, there was a net lateral movement of soil. A machine with, for example, 11 shanks would be equipped with five right-hand and six left-hand twisted points. The result was that a wide groove and a large berm were left after a pass. The machine as shown in U.S. Pat. No. 4,403,662 was an improvement because it left a smaller groove and not as large a berm by using fore and aft sets of discs and an improved point.
In U.S. Pat. No. 4,538,689, there is disclosed a winged point mounted on a parabolic shank. That winged point, in the combination shown, creates a large, rough surface similar to the surface of the moldboard plow used during the late 1970's and early 1980's. The wings on these points are set at a soil lift angle of approximately 30°. This lift angle was conventional at the time, but it is an aggressive angle which causes the wings to lift the soil abruptly. In some soils, particularly more compacted soils, the combination of an aggressive lift angle on the wings of the point, together with a parabolic shank, which is designed to lift and heave soil, lifted larger soil chunks and threw them out of the paths of the chisel plow and away from cooperating discs, making it difficult to create a level soil surface after a pass of the machine.
During the 1980's, farmers desired less tillage to prepare for planting. The furrows left by the chisel shanks had to be filled with the berms that were created between each shank. In order to fill these furrows behind large parabolic shanks, smaller shanks were placed to run shallower and were placed midway between the large chisel shanks. This resulted in smaller grooves on reduced centers. With the development of the disc leveler shown in U.S. Pat. No. 5,080,178, the furrows behind the shanks were substantially filled without leaving substantial grooves after the shanks had passed, thus improving the levelness or “smoothness” of the surface.
In heavily compacted soils, a parabolic shank lifts out large chunks of soil and heaves them to the path of least resistance around the shank. These large chunks are difficult to rearrange in such a way as to give a smooth resulting surface. If a chunk is rather large, it will tend to ride up the shank, roll forward and not be in the proper location for the leveler to roll it back to its original location, because the leveler primarily moves the soil laterally, not backward.
SUMMARY OF THE INVENTION
The present invention is directed to a tillage system, which is designed to perform complete tillage of the soil in a single pass while leaving a fairly level surface to reduce the amount of soil preparation required for planting the next season. Specifically, the present system cuts and buries residue, provides shallow tillage with discs, and provides a controlled amount of primary (deeper) tillage without creating a plow sole. As used herein, primary tillage means deep soil plowing, in a range of approximately nine to fourteen inches or greater. Shallow tillage may be in a range of three to six inches approximately. Finally, a leveler smooths the surface behind the chisel shanks.
The overall system functions are achieved through the cooperative action of widely spaced forward disc blades (sometimes referred to as the tillage discs to distinguish them from the trailing leveler discs) followed by chisel plows with winged points. Each plow point is located to the side of a strip of soil left untilled by the forward discs. The tillage discs are arranged in a forward set and a rear set with adjacent discs being offset in the direction of travel. One disc from the forward set and an associated one from the rear set cooperate to till adjacent swaths and move the soil (and residue if any) in opposing lateral directions. The tillage discs are arranged in cooperating pairs. A cooperating pair of tillage discs includes one disc from the forward set and one from the rear set with their working surfaces facing each other (i.e., in laterally “opposing” relation). Adjacent sets of cooperating discs are spaced with one disc from the forward set and one disc from the rear set having their non-working surfaces spaced to leave a strip of untilled soil.
By running the tillage discs at an operating depth in the range of approximately three to six inches, large chunks capable of riding up the plow shank are avoided. Further, some of the tillage discs run nearly in-line ahead of the shanks. That is, the shanks are placed to run adjacent to the edges of the strips of untilled soil left by the tillage discs. The discs provide a notch effect, leaving a furrow fairly closely aligned with the shank. Thus, the disc cutting into the previously untilled soil creates a furrow and the trailing plow, with its point working at a deeper level, is located near the furrow created by a forward tillage disc, at the edge of an untilled strip. This relationship permits the plow more easily to break through the compacted soil with less energy imparted to the soil, reducing a tendency to create large clumps of soil.
The action of the tillage discs is characterized by an aggressive tilling of the soil and top residue. By aggressive action, it is meant that each tillage disc on the forward set is placed at an operat
Case Corporation
Novosad Christopher J.
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