Patent Description:
A first category of replaceable blades for agricultural use such as disc blades, coulter blades and planter blades often have a circular sharpened outer periphery. These blades that are typically rotatably mounted on a shaft and they rotate about the shaft due to contact with the soil as the implement moves over the top of the ground. <CIT>shows gangs of discs of this type. Because of the circular shape, there is slippage between the blade and the ground as the blade is towed through a field, meaning essentially that the rotation of the blade is not constant even when the frame to which the shaft is attached is moving constantly in a forward direction. This slippage causes the blades to not cut the trash in a consistent manner. As the blade slips, trash will build up in front of the blade before the blade goes over the trash to cut it. This results in incomplete and inconsistent cutting of the trash.

A second category of replaceable blades of the aforementioned type have notches, flutes or waves which cause the blade to constantly rotate without slipping as the implement to which they are attached moves forwardly over the surface of the ground. Cutting surfaces on the outer periphery of notched blades are usually not sharp inside the notches, but only on the original circular portion of these blades before the notches have been cut out from them. In those blades, such as those shown in <CIT>, trash is trapped in the notches but the notched portions do not always cleanly cut the trash though the notched portions of the blades may tear the trash into pieces to some extent.

Even if the notched portions of the notched blades were to be sharpened, for example as shown in <CIT>, an irregular pattern in the cutting edge results in inconsistent cutting of the trash.

Fluted and wavy coulters or discs, for example as shown in <CIT>, has an outer peripheral cutting surface that is formed on the blade when it is circular and then the waves are formed into the blade during a hot forming step, making the cutting surfaces still close to being formed along a circular path that is moves from one side and then to the other side from a plane perpendicular to the axis of rotation of the blade. So there is very little trapping of trash between one wave of the outer periphery and the next adjacent one as the blade rotates and passes through the soil. This is in contrast to the aforementioned notched blades that trap trash in the notches as the blade rotates through the soil.

<CIT>has a clover leaf like design that is mounted on a shaft. A disc set <NUM> is seen in <FIG> of Javerlhac is mounted fixed to a shaft for rotation with the shaft. The blades do not rotate on the shaft independently of each other. The Javerlhac blades are out of phase so Javerlhac's device will work like a plow in that the lobes of one disk throw dirt to the next adjacent one sequentially. The blades <NUM> of <CIT> similarly rotate with the shaft on which they are mounted and do not rotate on the shaft independently with other blades that are disposed for rotation independently on the same shaft. Consequently blades like those of Javerlhac and Cahoy that are designed to rotate with the shaft with other similar blades out of phase rotating on the same shaft fall into a third category of blades.

Planter blades are used on a planter or drill for cutting a slot in the ground and are also used to open a furrow so that seeds may be dropped in the furrow before the seeds are then covered up by closing the furrow and packing down the soil over the seeds. These planter blades, for example as shown in <CIT>, are typically just a round flat steel disc with a sharpened outer peripheral edge, but it is extremely important that each planter blade penetrate the ground and cut trash if trash is in the path of the planter blade. It is critical that trash not build up in front of a planter blade, which is prone to happen when that blade has a typical prior art type circular outer periphery cutting surface on it.

The documents <CIT>, <CIT> and <CIT> represent further known agricultural tillage blades.

Accordingly, there is a need for a disc, coulter or planter blade that cuts trash and penetrates the soil better than those available in the past.

The present invention relates to an improved agricultural disc, coulter, planter/drill blade with an outer periphery substantially in the shape of a sine wave disposed about a circle.

The solution to the technical problem is achieved by the subject-matter of independent claim <NUM>, defining per se the invention. Particular embodiments of the invention are defined in the dependent claims.

The blades of the present invention will penetrate the soil farther, while at the same time, trapping trash in the depressions of the blade so as to cut trash better than previously known blades of this type.

The above needs are at least partially met through provision of the apparatus described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:.

For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.

Referring now to the drawings, wherein like reference numerals indicate identical or similar parts throughout the several views, <FIG> shows a sine wave formed along a horizontal line just to illustrate the basic configuration of a sine wave as applied to the outer periphery of a tillage disc, coulter, planter blade or the like.

Referring now to <FIG>, a flat agricultural blade or plate <NUM> has an outer periphery having five (<NUM>) projections 10p and an equal number, five (<NUM>), depressions 10d formed evenly in the form of a sine wave superimposed onto a circle <NUM>, shown in dashed lines. A center opening <NUM> is also disposed in the plate <NUM>.

<FIG> shows a blade <NUM>, which is similar to the blade <NUM>, except that it has twenty five (<NUM>) projections 20p and an equal number, twenty five (<NUM>), depressions 20d formed evenly in the form of a sine wave superimposed onto a circle <NUM>, shown in dashed lines in <FIG>. It has been determined that for blades of typical diameters used for agricultural tillage purposes, no fewer than five (<NUM>) projections/depressions and no more than twenty five (<NUM>) projections/depressions are workable. Fewer than five projections/depressions traps too much trash to be cut in the depressions and more than twenty five projections/depressions is too close to being equivalent to just having a circular blade with no depressions at all. A center opening <NUM> is disposed in the blade <NUM> for permitting it to rotate on a shaft, like shaft <NUM> shown in <FIG>. The blades <NUM> rotate independently on the shaft and preferably do not rotate with the shaft. The shaft <NUM> can remain fixed with respect to the tool bar <NUM> as shown in <FIG>.

<FIG> graphically shows the mathematical function for the outer periphery of the coulter is: r = R + A sine(TΘ) where r is the radius (distance from the origin) of the outer periphery, R is the average radius (half the average diameter), A is the amplitude of the sine wave superimposed on the circle, and T is an integer (only) dictating the number of full periods of the sine wave appearing around the periphery. The outer black line that includes projections 30p and depressions 30d, is the wavy outer periphery and the circular dashed line <NUM> is the average radius. T = was selected to be <NUM> in this example. In <FIG>, the disc <NUM> has nine (<NUM>) projections 30p and nine (<NUM>) depressions 30d between each projection 30p, the sine wave formed by the outer periphery being formed along a circle represented by dashed line <NUM>.

<FIG> show a flat agricultural blade or plate <NUM> which has an outer periphery having seven (<NUM>) projections 40p and an equal number, seven (<NUM>), depressions 40d formed thereon. A center opening <NUM> is also disposed in the plate <NUM>, along with optionally four bolt holes <NUM> for optionally bolting a bearing structure (not shown) onto the blade <NUM>.

<FIG> shows a cross sectional view of the sharpened edge 40sea that goes completely around the outer periphery of the blade <NUM>. <FIG> shows an alternate edge with sharpened edge surfaces 40seb and 40sec that can alternatively be formed on the outer periphery of the blade <NUM>, instead of edge 40sea, if desired.

<FIG> shows the convex side a concave/convex agricultural disc <NUM> which has an outer periphery having seven (<NUM>) projections 50p and an equal number, seven (<NUM>), depressions 50d formed thereon. A center opening <NUM> is also disposed in the plate <NUM>, along with optionally four bolt holes <NUM> for optionally bolting a bearing structure (not shown) onto the blade <NUM>.

<FIG> shows a cross sectional view of the sharpened edge 50se that goes completely around the outer periphery of the blade <NUM>. The agricultural tillage blade <NUM> has radially outermost portions of the sharpened outer periphery of the blade lie generally in a first plane B but the central portion of the disc is disposed at least partially in a second plane A, which second plane A is parallel to but spaced from the first plane B.

<FIG> shows the concave side of the concave/convex agricultural disc <NUM> of <FIG>. The disc <NUM> has an outer periphery having seven (<NUM>) projections 50p and an equal number, seven (<NUM>), depressions 50d formed thereon. A center opening <NUM> is also disposed in the plate <NUM>, along with optionally four bolt holes <NUM> for optionally bolting a bearing structure (not shown) onto the blade <NUM>.

The agricultural tillage blade <NUM> shown in <FIG>, as in <FIG>, has radially outermost portions of the sharpened outer periphery of the blade that lie generally in a first plane B but the central portion of the disc is disposed at least partially in a second plane A, which second plane A is parallel to but spaced from the first plane B. This is generally to be distinguished from flat coulters or flat planer/drill blades.

<FIG> shows the convex side a concave/convex agricultural disc <NUM> which has an outer periphery having fifteen (<NUM>) projections 60p and an equal number, fifteen (<NUM>), depressions 60d formed thereon. A center opening <NUM> is also disposed in the plate <NUM>.

<FIG> show the concave side of the concave/convex agricultural disc <NUM> of <FIG>. The disc <NUM> has an outer periphery having fifteen (<NUM>) projections 60p and an equal number, fifteen (<NUM>), depressions 60d formed thereon. A center opening <NUM> is also disposed in the plate <NUM>. <FIG> and <FIG> show a sharpened edge 60se that goes continuously around the outer periphery of the disc <NUM>, continuously through all projections 60p and all depressions 60d.

<FIG> is a partial cross sectional view of the concave side of the concave/convex disc of <FIG> rotating in a clockwise direction, penetrating the soil, trapping trash such as corn stalks <NUM> in the depressions on the outer periphery and cutting the corn stalks <NUM> while at the same time, due to the concave/convex shape, throwing some soil in a direction away from the side being viewed in <FIG>, on the concave side of the blade. <FIG> shows the disc <NUM> moving through the soil to cut trash such as cornstalks <NUM> that become trapped in the depressions 50d between adjacent projections 50p as the disc <NUM> rotates clockwise in the example shown in Fig. <NUM>. By having a minimum of five or a maximum of twenty five projections/depressions, this trapping of the trash between projections and then cutting the trash as the depression part of the blade pushes against the trash/cornstalk <NUM> as it goes into the ground does a much better job of cutting the trash than prior art blades. The projections, like 50p, penetrate the soil farther than prior art blades and better facilitate the trapping of the trash such as cornstalks <NUM> in the depressions, like depression 50d. A blade that has both better soil penetration and better cutting of the trash is a major advantage of the present invention.

<FIG> show a gang of discs, like the discs <NUM> of <FIG>, that rotate independently on a shaft <NUM>. This is fundamentally different than the gangs of discs shown in <CIT>, which discs are attached to a rotating shaft and are intentionally mounted sequentially out of phase to throw the soil to the next adjacent blade, etc..

Claim 1:
An agricultural tillage blade comprising:
a plate (<NUM>, <NUM>) having a central opening (<NUM>, <NUM>) adapted to be disposed on a shaft for rotation
the plate having an outer periphery that is exactly in the shape of a sine curve formed about a circle;
the outer periphery being sharpened to more easily penetrate the soil and cut trash;
wherein the radially outermost portions of the sharpened outer periphery of the blade lie generally in a first plane (B); and
wherein the central portion of the disc is disposed at least partially in a second plane (A), which second plane is parallel to but spaced from the first plane.