Seed firming assembly and method for agricultural seeders and mounting system therefor

A seed firming assembly and method for agricultural seeders includes a large diameter seed-firming wheel for firming seeds into soil at the bottom of a furrow. The seed-firming wheel is located immediately behind a furrow opener and a seed guide. The seed-firming wheel is rotatably supported by an attaching arm, which is pivotally attached to a planter subframe at a location behind the seed-firming wheel so as to push the seed-firming wheel in a forward direction during operation. The attaching arm has a forward portion on which the seed-firming wheel is rotatably supported, a rearward portion on which an extension spring is attached for imparting a downward force on the seed-firming wheel during operation, and a horizontal transverse axis of rotation located between the forward and rearward portions. An adjustment mechanism is provided for adjusting the downward force imparted on the seed-firming wheel by the spring.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to agricultural seeders that produce open furrows in the soil into which seeds are placed, and more particularly, to an improved seed firming wheel and method of attaching and operating said firming wheel for use with such seeders in securing seed-to-soil contact.

2. Description of the Prior Art

Agricultural planting methods continue to evolve in response to widespread adoption of “no-till” or “reduced-till” crop production techniques with greatly reduced dependence on tillage of the soil, and in which the next crop's seeds are often placed directly into the previous crop's stubble or crop residues. No-till or reduced-till seeding differs greatly from seeding into a tilled seedbed. The soil conditions for no-till seeding are typically wetter than those dried by tillage, due to the mulching effect of the crop residue remaining on the soil surface. No-till soils are also typically more structurally stable than tilled soils, as the soil particles are “aggregated” or held together by old roots, fungi, and other organic substances and molecular attractions binding the particles together.

The value of pressing newly planted seeds into the soil has likely been known since the dawn of agriculture, and in-furrow firming wheels were clearly described and depicted at least as early as 1908 in Davis, U.S. Pat. No. 939,812. Some earlier “presser” wheels are taught by Patric et al., U.S. Pat. No. 404,108, issued in 1889, although these firming devices were relatively wide and further rearward than the device described in Davis '812. These early firming devices also essentially allowed (and relied upon) considerable loose soil to slough into the furrow ahead of the firming device, and are more in the vein of a modern ‘packer’ or ‘press’ wheel operating upon the soil surface and compressing all of the soil filled over the seed. Arnett, U.S. Pat. No. 345,403, issued in 1886, in describing a down-force system of dead weights for drill openers because “machines of this type, which are commonly operated on unplowed sod-land . . . ” [lines 18-19], also depicts press wheels “for the purpose of closing the furrow and covering the seed” [lines 47-48] which were apparently intended to also achieve seed firming to some extent. The different methods and actions of such wheels on freshly formed furrows and planted seeds becomes still more important in no-till conditions due to the greater structure or resilience of no-till soils as compared to tilled soils, which renders pressing from the soil surface ineffective and damaging to the seed environment. Soils which are eroded or which have otherwise suffered degradation from tillage, as well as soils that naturally have high clay content and/or low organic matter content, will be more susceptible to damage from excessive pressing above the seed, especially when those soils are damp.

In no-till seeding, the wetter and more structured soils generally prevent press wheels on the soil surface from performing the seed-firming and furrow-closing functions adequately. The sidewall of the furrow formed in no-till seeding does not crumble easily as does the sidewall in tilled conditions, where the soil had previously been loosened and fluffed by tillage. Accordingly, very high pressures are sometimes applied to the packing or closing wheels in an attempt to squeeze the furrow sidewalls back together. This typically results in poor seedling emergence because the soil in the furrow is more compressed at the surface compared to soil near the seed, sometimes to the extent of having a void immediately above the seed but with extremely compressed soil at the surface. In this instance, seed germination may fail due to the drying of air in the void, or the seedling may leaf underground in the void, or the seedling will encounter great difficulty pushing itself through the dense layer of soil, which will slow and weaken the seedling or even kill it.

Some improvements have been made by separating the seed firming and furrow closing functions. This is typically only possible where the depth-gauging function is already accomplished independently of the packing or closing wheel, as in the configuration where depth-gauging wheels travel alongside the furrow opening discs. Seeds are firmed into the soil in the bottom of the furrow by a narrow rolling wheel or sliding-type firmer exerting a relatively small amount of pressure onto the seed after it has been placed by the furrow openers and seed-directing tube.

The lineage of rolling in-furrow firming wheels extends down through the years, including firming wheels affixed to the opener subframe so as not to move during field operation (as taught by Lemmon, U.S. Pat. No. 2,577,775, and Jennings et al., U.S. Pat. No. 4,307,674), firming wheels suspended from a closing frame, and firming wheels such as Davis '812 wherein the wheel and trailing attaching arm is free to pivot vertically and urged downward by a spring tensioning device (such as further taught by Yoder et al., U.S. Pat. Nos. 5,826,524 and 5,724, 903; and by Johnson et al., U.S. Pat. Nos. 5,398,625, 5,494,339, and 5,676,429). Some of the small-diameter (e.g., 5-inch diameter) firming wheels, such as envisioned by Yoder and Johnson, did in reality encounter numerous difficulties in field operation including mud and stubble accumulation near the wheel's axis of rotation and including the juncture with the attaching arm. Other difficulties have ensued with the attaching arm and spring apparatus being located between (on “double-disc” designs) the furrow-opening blades and gauge wheels, which contributes to mud and straw accumulation, as well as making awkward the adjustment and service of the attaching arm and spring. Most of the planter models sold in North America in the last 30 years have subframes that extend rearward of the opener blades and gauge wheels, preventing the simple installation of large-diameter firming wheels in close proximity to the blades.

As compared to small firming wheels, the large-diameter (9-or 10-inch) firming wheels of appropriately narrow construction have encountered considerably more success, such as what is taught by Bigbee (U.S. Pat. No. 4,760,806) and improved by Prairie et al. (U.S. Pat. No. 6,386,127), embodied in the firming wheels of the John Deere 50, 60, and 90-series models of single-disc opener grain drills and in the Case-New Holland SDX series of drills, respectively. These prior art designs utilize a firming wheel mounting that enables the wheel and attaching arm to pivot vertically from the upper or forward end of the attaching arm, such that the wheel is able to move independently of the opener. In this way, the wheel and arm are trailing from the radial pivot point. Trailing arms generally require substantial pressure to ensure sufficient firming action by the firming wheel, and often are further rearward than desired, due to the necessities of clearance for the arc of travel of the firming wheel during field operation.

Virtually none of the planter models currently marketed in North America employ large-diameter in-furrow firming wheels (or any in-furrow firming device at all), apparently because packing the soil from the surface downward is perceived as adequate by the currently dominant tilled-seedbed market. However, small-diameter (approximately 5-inch) “seed-lock” firming wheels, and the attaching mechanisms from which the wheel trails, have at various times been sold in the North American markets by both OEM planter manufacturers (Kinze, J D, Great Plains, AGCO White) as well as aftermarket suppliers (Yetter, J S Ag Innovations). These small-diameter wheels were quite popular for a few years in the mid-1990s, until the realization that plugging with mud and crop residues was a serious problem.

Sliding seed-firming devices also have a long history, appearing (but not described) in 1889 in Patric et al. '108, although as previously discussed, the device was neither shaped nor positioned to function in the furrow proper, but rather the device would likely operate in the vestiges of the furrow and on top of considerable loose “fill” soil that had sloughed back into the furrow after the opener blades had passed, and the relatively wide Patric firming device itself would likely tend to drag still more soil into the furrow with its forward end as it slid. The “presser-foot” is further depicted in Patric et al., U.S. Pat. No. 410,438, and in Packham, U.S. Pat. No. 530,962. More recent inventions have been true in-furrow sliding firming devices, such as described in Keeton, U.S. Pat. Nos. 5,425,318 and 5,673,638, as well as Peterson et al., U.S. Pat. No. 6,119,608. Many of these sliding firming devices are hindered in their performance by mud or damp soil accumulation on the lower edges, especially if some soil disturbance occurs ahead of the firming device so that it no longer is operating in a ‘clean’ cut, or if insufficient pressure is applied to the sliding firming device. Soil accumulation on the underside of the firming device can result in dragging of seeds, and in a poor firming action. Sliding firming devices may also exhibit rapid wear in many soil conditions, unless made from exotic materials.

SUMMARY OF THE INVENTION

After extensive field testing, the Applicants developed an improved seed-firming wheel linkage which is the subject of the present invention. The seed-firming wheel linkage of the present invention solves the mechanical problems of fitting a large-diameter in-furrow firming wheel in close proximity to the opener blades on various seeder opener designs, especially modern double-disc planter designs. The present design provides improved clearance of mud and crop residues, allows easier access for service and adjustment of the linkage, and also allows a reduction in spring pressure urging the firming wheel downward since the wheel is pushed instead of pulled.

The Applicants' invention utilizes a large-diameter firming wheel with a narrow tapered edge to allow it to fit into the bottom of the furrow “V,” with the wheel preferably manufactured of a flexible rubber material across much of its diameter to allow substantial flexing and thereby permitting the wheel to track the furrow effectively while seeding on slight contours. The firming wheel is rotatably attached to a stem or arm, which extends forward from a point on the opener subframe rearward of the firming wheel itself, such that the wheel is pushed rather than pulled. The arm pivots on a shaft horizontal to the soil surface and transverse to the direction of travel. Preferably, the wheel is biased downwardly so as to keep the wheel engaged in the soil at all times and to supply additional firming action by it. The downward bias is accomplished by spring pressure on the arm.

Rearward of the firming wheel are closing wheel(s), which are attached on separate supporting arm(s) to allow pivoting upward by the wheel(s).

The Applicants' invention provides a method whereby the firming wheel can be located in close proximity to the furrow opening blades, gauge wheels, and seed-drop tube. This arrangement allows the pivot point of the firming wheel to be more accessible for service, allows the firming wheel to better track the furrow while planting on the contour, and requires little vertical travel for the firming wheel due to its proximity to the depth gauging wheels.

This arrangement also allows for the portion of the arm(s) passing alongside the firming wheel to the wheel's rotatable axis to be located further laterally from the wheel's side(s), which would otherwise be constrained by the relatively narrow space between the opener blades and gauge wheels. Having sufficient clearance between the wheel and the arm passing alongside the wheel allows mud and straw to pass freely as these will on occasion be directed into this juncture by the firming wheel's rotation, and by the dynamic of the other planter components travelling through a stalk- or stubble-strewn field.

Numerous other objects and advantages of the present invention will be apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of the present invention, simply by way of illustration of one of the modes best suited to carry out the invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various obvious aspects without departing from the invention. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive.

DETAILED DESCRIPTION OF THE INVENTION

Improved in-furrow seed firming wheels for agricultural seeders according to preferred embodiments of the present invention will now be described in detail by reference toFIGS. 1 to 5of the accompanying drawings.

FIG. 1is a side view of a common planter opener unit12, utilizing a prior art seed firming and closing system. The planter opener unit12is attached to the frame or toolbar of the planter by means of a parallel linkage22with springs or other devices (not shown) for supplying down-pressure to penetrate the previous crop residues14and soil19. The planter opener unit12employs two opener discs24that are rotatably mounted to an opener subframe26for creating a furrow. The opener discs24are in contact with each other at the lower leading edge but slightly gapped at the upper and rearward edges to allow a seed-directing tube30to pass between them. The tube30guides seeds16to the bottom of the furrow. Planter opener units usually have two depth-gauging wheels28, one alongside each opener disc24. A seed hopper52is also shown which carries a supply of seed to be delivered to the furrow through the seed tube30.

A small-diameter seed-firming wheel32on the planter opener unit12performs the function of firming the seeds16into the soil comprising the furrow bottom. Alternatively, sliding firmers (not shown) are sometimes used to perform this function (note that in some configurations the separate firming mechanism is omitted—both the firming and closing functions are performed by smooth or tined closing wheels operating alongside the furrow which compress the sidewall downward starting from the soil surface; however, this method usually performs poorly in no-till). The firming wheel32is rotatably attached to the planter opener subframe by an arm31which pivots at its forward end to allow the arm and wheel to move vertically in response to minor variations in furrow depth and undulating terrain. The wheel32and arm31have considerable upward travel to prevent damage when traversing small gullies or passing over rocks or other obstacles.

The firming wheel has an axle33that is low to the soil surface17due to the relationship between the wheel diameter and the depth of planting, which is commonly in the range of 1.0 to 2.5 inches. The axle33and juncture with arm31tend to accumulate mud and previous crop residues14during field operation. The arm31passes in relatively close proximity alongside the edge of wheel32due to space constraints imposed by the gauge wheels28and opener blades24as well as the necessity of positioning the wheel32as far forward as possible to maintain some semblance of alignment when seeding on the contour, and to allow clearance of the wheel32in relation to the opener subframe26as the wheel32and arm31pivot upward significantly to clear obstacles during field operation. The substantial upward travel capability of the wheel32is also necessary to prevent damage to the apparatus holding the forward end of the arm31and securing it to the forward portion of the opener subframe26between the blades24. The robustness of this apparatus is constrained by the space between the blades24and alongside the seed tube30and is further compromised by the leverage that the wheel32and arm31can exert on these components while in field operation. Firming wheel32diameter is also constrained by the clearance issues involved during vertical pivoting.

Rearward of the firming wheel32, the closing wheels36are mounted from a unibody bracket34which has the ability to pivot vertically and radially about a single point located on a subframe of the opener unit12immediately rearward of the opener discs24.

FIG. 2is a side view of a planter unit according to an embodiment of the Applicants' invention. The same reference numerals are used inFIG. 2to depict various components that correspond to those shown inFIG. 1. In this embodiment, the diameter of the firming wheel32A is substantially greater, so that the axle33remains well above the soil surface17and clear of mud and crop residues14during normal seeding operations (i.e., planting depths of 1 to 3 inches). The firming wheel32A has a narrow tapered edge to allow the wheel to fit into the bottom of a furrow, and a flexible portion that permits the wheel to flex and track the furrow effectively while seeding on contours.

The attaching arm(s)31A rotatably support the seed-firming wheel32A and are pivotally attached to the planter subframe26behind the seed-firming wheel32A so that they push, instead of pull or draw, the seed-firming wheel32A in a forward direction during operation. The furrow opener discs24are pivotally attached to the planter subframe26at a location in front of the seed-firming wheel32A. A front portion of the seed-firming wheel32A is disposed between the opener discs24during operation, as shown inFIGS. 2 and 3. This configuration makes installation and serviceability much easier, reduces stress on the front of the subframe26, requires less spring pressure on the arm(s)31A, and allows the arm(s)31A to pass alongside the firming wheel32A at a greater lateral distance from the surface of the firming wheel32A to facilitate self-clearing of mud and debris that might otherwise accumulate in the axle33area and the juncture of the axle33and the arm(s)31A.

Rearward of the firming wheel32A are the closing wheels36for closing the furrow. The closing wheels36are mounted to independent attaching arms34′ which each have the ability to pivot radially at their attachment point to the opener subframe26, and may be downwardly biased by spring pressure or other means.

FIG. 3is a side view of a planter unit according to another embodiment of the Applicants' invention. This embodiment differs from that depicted inFIG. 2in the arrangement of the closing wheels36. Here, the closing wheels36are on a unibody bracket34, which pivots radially at its attachment point to the opener subframe26. Other components are the same as those labeled and described in conjunction withFIG. 2.

FIG. 4is top plan view of a planter row unit opener of the same design as inFIG. 2. The same reference numerals, letters, and symbols are used inFIG. 4to depict various components that correspond to those shown inFIG. 2. Additionally, a cutaway view of the attaching plate75(largely obscured in previous figures) is shown, which attaches to the trailing portion of the subframe26in the location previously accommodating the attachment of the unibody closing wheel frame34as inFIG. 1. Attaching plate75is affixed to a shaft72which forms the axis of rotation for the firming wheel attaching arms31A. The axis of rotation of the attaching arm(s)31A is horizontal to the soil surface and transverse to the direction of travel. As seen inFIG. 4, a pair of attaching arms31A are used, and the seed-firming wheel32A is rotatably supported in the space between the arms31A such that a large gap exists between the outer surface of the wheel32A and the inner surface of each arm31A, preferably a gap of approximately one inch or more. Inserted into the attaching arms31A are hat bushings71that fit loosely over the shaft72. The arms31A are secured to each other by a bolt through the firming wheel axle33and also by a bolt74at the rearward edge of the arms31A. Thus, the hat bushings are ‘sandwiched’ or contained, and need no further securing. Plate75also holds a new pivotal attaching point35for the closing arms34′.

FIG. 5is a side elevation view of the spring tensioning device and adjustment thereof for the firming wheel attaching arms31A and firming wheel32A (the firming wheel32A is shown inFIGS. 2 to 4). As seen inFIG. 5, the attaching arm(s)31A have a forward end portion on which the seed-firming wheel32A is rotatably supported on the axle33, a rearward portion on which an extension spring78is attached to the bolt74for imparting a downward force on the seed-firming wheel32A during operation, and an axis of rotation formed by the shaft72located between the forward and rearward portions. The bolt74holds the lower hook of the extension spring78. The extension spring78extends upward from the lower hook. An upper hook of the extension spring78is inserted into the lower end of a sliding handle76, which provides an adjustment mechanism for the spring78. The handle76is adjustable by vertical sliding, and secured by a pin80in any of a plurality of holes77in the handle76. The pin80becomes seated into a transverse recess84in the plate75and is held in place by constant spring tension from the extension spring78. The spring78pulls upward on the arms31A rearward of their pivot point on the shaft72, thereby biasing the forward ends of the attaching arms31A and the firming wheel32A downward.

Although the handle76is shown inFIG. 5as an L-shaped member, it should be understood that a T-shaped handle or other suitable structure can be used to improve the ease of gripping the handle during adjustment.

The spring78can be an extension spring as shown inFIG. 5. Alternatively, other types of biasing means for applying pressure to the attaching arms31A can be used instead of an extension spring, including rubber straps, gas-filled cylinders, shock absorbers, and so forth.

In another alternative, the attaching arms31A for the firming wheel32A can have their pivot point located at the most rearward point of the attaching arms31A instead of between the front and rear ends as shown in the illustrated embodiment. In this case, the biasing means for applying downward pressure can be in the form of a compression spring or gas-filled cylinder or the like that pushes down on the attaching arms31A forward of the pivot point.

The seed firming assembly of the present invention is particularly suitable for use in no-till and reduced-till planting systems because of its ability to clear mud and crop residues. However, the assembly will also work well in tilled soil and can be adjusted easily to accommodate different seeding conditions by using the adjustment mechanism for the spring78described above.

While the invention has been specifically described in connection with specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.