Abstract:
An opener assembly for an agricultural seeder has an opener disc attached to an opener subframe for rotation about an axis. The opener disc is angled to the direction of travel to create a furrow for depositing seeds. A boot is mounted to the opener subframe beside the opener disc for preventing loose soil from falling into the furrow ahead of seed deposited therein. The boot contacts and scrapes the opener disc and creates an enclosure between the boot and the opener disc. A flexible seed bounce flap provides the rear wall of the enclosure. The boot has a lower edge that fits entirely within the furrow created by the opener disc. A seed tube having a lower end extending into the enclosure is mounted to the opener subframe by a bracket independently of the boot. A structure is also provided for limiting downward movement of a firming wheel arm.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    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-directing tube and boot, and method of attaching and operating the tube and boot for use with such seeders in obtaining improved seed placement in the furrows. 
         [0003]    2. Description of the Related Art 
         [0004]    Agricultural planting methods continue to advance 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&#39;s seeds are often placed directly into the previous crop&#39;s stubble or crop residues. No-till or reduced-till seeding differs greatly from seeding into a tilled seedbed. Although the soil conditions for no-till seeding are typically characterized by more structural stability 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, it is still of considerable importance to prevent loose soil and “duff” (chaff and small pieces of partially decomposed mulch) from entering the seed furrow prematurely, before the seeds have come to rest at the bottom of the furrow. This is of particular importance on single-disc opener designs which are particularly vulnerable to loose soil and duff sloughing into the furrow after the opener disc has passed, relying on soil stability and/or a seed boot to inhibit the loose soil and duff from entering the furrow until after the seeds have been adequately placed in the bottom of the cut furrow. 
         [0005]    Single-disc opener designs for seed or fertilizer placement have met with considerable success in no-till seeding, partly due to simplicity. Because of the structural stability of no-till soils, much higher down-force requirements are imposed on the opener disc to cut the furrow to a consistent depth. This additional strain generally necessitates more robust opener discs together with a much larger hub and mechanical bearing(s) on which the opener discs are rotatably mounted, and this durability requirement also lends an advantage to the single-disc design for cost and space constraints. Larger hubs and bearings on the opener discs can interfere with the routing of seed-delivery tubes and positioning of gauge wheels. 
         [0006]    Gauge wheels pose a design problem because the most desirable positioning is with the gauge wheel contacting the soil most forcefully at the point where the opener disc&#39;s rearward edge is rotating up out of the soil. This allows the gauge wheel to control “sidewall blowout,” which results from the opener disc&#39;s upward rotation and angle to the direction of travel causing the furrow sidewall to tear apart and lift upward, i.e., following the disc&#39;s rotation upward as it exits the furrow. When left unchecked, sidewall blowout sometimes results in the furrow sidewall tearing completely free and being flung out of the furrow by the opener disc&#39;s momentum, thereby creating an irregularly shaped furrow and/or allowing pieces of the sidewall to enter the furrow before seeds have been properly placed. 
         [0007]    The opener disc is typically mounted at a slight angle to the direction of travel so that it is pushing soil laterally to create a furrow. For controlling sidewall blowout, gauge wheels generally are mounted in the same plane as the opener discs, with the inner lip of the gauge wheel flush against the outer edge of the opener disc (“outer” refers to the side away from the furrow being cut). With a 16-inch or 18-inch diameter opener disc (the preferred disc sizes due to optimal cutting ability at 1.5- to 2-inch seeding depth; larger sizes hairpin more mulch, and smaller sizes are more prone to plugging or “bulldozing” of clumps of straw or debris), and a 15-inch gauge wheel (again, the preferred size, since smaller sizes resist rolling over small obstacles in the field, and larger sizes get in the way of other components), the forward edge of the gauge wheel is then approximately at the axis of the opener disc, which prevents the opener disc&#39;s hub from being located on the outside of the opener disc, especially if it is a large heavy-duty hub (“outside” refers to the side away from the furrow being formed). Hence, a double-disc design has somewhat limited options as to where to locate relatively large hubs, since the opener discs must be at a narrow angle to each other to cut the soil properly, with such relationship physically precluding large hubs from being between the discs. On the single-disc design, the large hubs are typically located on the opposite side of the opener disc from the gauge wheel, which is the inside of the opener disc. 
         [0008]    With a large hub on the inside of the opener disc, the seed delivery tube must pass either ahead of the hub or behind it. If the seed tube passes in front of the hub, the trajectory of the seeds passing inside the tube will be approximately at a 45-degree angle to the furrow (in the horizontal plane of the soil when on level terrain), aimed rearward as much as downward, due to the need for the seeds to enter the furrow when it has appreciable width, which would be directly below the hub and rearward of it. The rearward seed trajectory poses a significant problem of ricochet, which is the tendency of the seeds to bounce upward and out of the furrow after striking the soil or the opener disc after the seeds exit the seed-directing tube and/or boot. While a significant problem for grain drills with gravity-fed seed delivery, this problem is greatly exacerbated by forced-air delivery which has become commonplace on larger width drills called “air drills.” The seeds are carried in an air stream and move at a velocity greater than that attained by seeds falling solely under the influence of gravity, thereby increasing the ricochet effect. Further, if no provision is made for the pressure of the air stream to be vented or diffused to the ambient atmosphere until the seeds exit the lower end of the seed tube or boot, the air stream itself can carry lighter seeds out of the furrow as the air stream blasts into the furrow and then out of the furrow as it escapes. 
         [0009]    A single-disc no-till drill opener design that has met with great success in the marketplace is typified by the John Deere drill models 1590 and 1890, and their predecessor models 1560 and 1860 (hereinafter “Deere 60- and 90-series”), both of which are slightly updated versions of the basic opener design described in U.S. Pat. No. 4,760,806 issued to Bigbee, which was first embodied in John Deere drill models 750 and 1850 (hereinafter “Deere 50-series”). On the Deere 60- and 90-series openers, as well as the 50-series, the seed boot is held directly on the opener subframe via a single bolt, with the boot being able to pivot on the bolt&#39;s axis by a few degrees. The boot is urged toward the opener disc by a leaf spring secured in a recess below the bolt, which continually holds one side of the boot&#39;s forward/lower edge flush against the opener disc. The seed tube passes forward of the disc&#39;s hub and enters the top of the boot near the aforementioned bolt attachment point which is also ahead of the hub. 
         [0010]    A significant downfall of the design of the John Deere 50-, 60- and 90-series drill opener assemblies is the protrusion of the boot beyond the cut made by the opener disc (not operating in the “shadow” of the opener disc). This protrusion greatly inhibits the ability of the boot to be operated deeper than with the boot&#39;s lowermost edge approximately flush with the soil surface, due to the boot being relatively blunt on its lower edge and therefore resisting penetration of firm soil. Attempts to operate the boot more deeply in relation to the soil result in higher horsepower requirements, much higher down-force requirement on the opener unit (or a tendency for the opener to “ride out” and fail to maintain depth), and substantially greater wear on the boot and its attachment point. With the boot not extending below the soil surface, the boot has very limited ability to hold loose soil and duff out of the furrow while the seeds are being placed, as well as very limited ability to compensate for the ricochet effect of seed bounce. This seed bounce problem is exacerbated by the failure of the boot to extend below the soil surface, and by the remarkable failure of the seed bounce flap to enclose the rear of the boot, being situated at a 45-degree angle from vertical and in relation to the boot such that a sizeable gap occurs at the rear corner during field operation. The flap is the essence of U.S. Pat. No. 5,092,255 issued to Long et al., termed a “seed boot extension” therein, although commonly called a seed bounce flap in the industry. 
         [0011]    Other single-disc drill designs have routed the seed tube behind the opener disc&#39;s hub, resulting in the seed tube being more nearly vertical, and possibly angled slightly forward at the lower end. The more vertical orientation results in less seed ricochet, although it is quite important that the tube not be too far rearward in relation to the opener disc because of reduced control over seed placement, and it is also important that a boot and seed bounce flap adequately direct the seeds into the bottom of the furrow. This seed tube arrangement was integrated into a single-disc no-till opener that was marketed for several years (now discontinued) as Flexi-coil&#39;s “FSO” or “F/SO,” and is depicted in U.S. Pat. No. 6,237,696 B1 issued to Mayerle. With Mayerle &#39;696, the seed boot (a.k.a. “scraper”) is attached directly to the seed tube, which is itself rigidly attached to the opener subframe. The boot attaches to the tube via two bolts and by compressing a thin rubberized pad between the upper end of the boot and the tube. As the boot (scraper) wears against the opener disc, the bolts must be continually readjusted to keep the forward edge of the boot against the opener disc; neglect of this adjustment often results in weeds or straw becoming lodged between the boot and the opener disc, which eventually arrests the rotation of the opener disc or causes the opener to otherwise plug with straw or debris. However, the shape and location of the Mayerle &#39;696 boot and tube allow much greater precision in placing seeds at the bottom of the seed furrow as compared to the Deere 60- and 90-series. 
         [0012]    U.S. Pat. No. 6,216,616 B1 issued to Bourgault depicts a single-disc opener (lacking a gauge wheel; depth is limited only by down-force applied to the disc opener and by soil resilience which varies across the field) with a scraper or boot attached directly to the opener subframe, independent of the seed tube, and with the scraper or boot being rotatably mounted and spring-tensioned against the opener disc. The design has the seed tube routed rearward of the opener disc&#39;s hub. The general design of the Bourgault &#39;616 seed tube and scraper/boot arrangement overcomes some of the adjustment and straw plugging difficulties mentioned in the foregoing discussion of the Flexi-coil FSO (Mayerle &#39;696). However, the Bourgault scraper/boot design is almost entirely ineffective at holding loose soil and duff out of the furrow because of the failure of the scraper/boot to extend forward into the area where the disc is actually creating the cut, failure to extend sufficiently downward into the furrow, and failure to create any sort of enclosure at the rear of the tube or scraper. Furthermore, the Bourgault design (embodied in air drills sold by Bourgault Industries Ltd.) lacks the seed-placement precision of gauge-wheel openers such as the Deere 60- and 90-series, and also lacks separation of the seed-firming function from furrow closing (and from opener depth-gauging), all of which are agronomically desirable. 
         [0013]    Baugher et al., U.S. Pat. Nos. 5,595,130, 5,802,995, and 6,029,591, depict a single-disc opener with a tube passing rearward of the opener disc&#39;s hub, although with the boot (“runner”) attached directly to the tube. The entire boot and tube assembly pivots about a single attaching bolt or pin at the forward end of the assembly, and is biased toward the opener disc with a spring. In &#39;995 and &#39;130, the boot pivots about an axis that is mostly horizontal (with its axis along the direction of travel), while in &#39;591 it pivots about an axis that is nearly vertical. While the Baugher &#39;130, &#39;995, and &#39;591 patents retain most of the other functional elements of the Deere 50-, 60-, and 90-series opener, the seed boots and tubes depicted therein involve substantial revision of the opener design to accommodate the boot and tube; i.e., the boots and tubes depicted in these patents wouldn&#39;t fit existing Deere 50-, 60-, and 90-series openers, nor would any alterations allow the boots and tubes to fit those openers without a wholesale rebuilding of the opener subframe. The Baugher &#39;130, &#39;995, and &#39;591 patents also depict a seed tube which is still oriented somewhat rearward and not forward at its lower end, and also with the lower end of the tube located more rearward of the disc&#39;s axis than is desirable since the disc is useful in holding the soil and duff out of the furrow while seeds are being placed, and this occurs to the greatest extent where the disc is at the bottom of the furrow (i.e.,directly below the disc axis). Furthermore, the Baugher &#39;130, &#39;995, and &#39;591 patents depict seed boots without adequate enclosure of their lower rearward portions to prevent seeds from bouncing into undesirable locations, i.e., seeds not being adequately channeled into the bottom of the furrow. The prior art before Baugher also deployed seed and fertilizer boots (a.k.a. runners or shoes) with nearly identical shapes and construction, i.e, sufficiently narrow as to stay within the furrow cut by the disc. For example, such boots were used in single-disc gauge-wheel fertilizer openers sold by John Deere since the late 1980s on their row-crop planters. 
         [0014]    Yet another type of seed boot for single-disc drill openers is described in Wendling et al., U.S. Pat. No. 6,347,594 B1, with a substantially vertical seed tube passing rearward of the opener disc&#39;s hub. The seed tube is attached directly to a narrow boot that pivots about a bolt on a horizontal axis (along the direction of travel, and parallel to the opener disc). The boot and tube are biased toward the opener disc via a leaf spring. However, the boot and tube design and attachment method constitute a major departure from the Deere 60- and 90-series openers; thus, this boot and tube arrangement envisioned by Wendling in the &#39;594 patent could not be fitted onto those openers without a wholesale rebuilding of the opener subframe. The opener depicted in the &#39;594 patent has trailing wheels and arms for covering or packing that are dramatically different from the Deere 50-, 60-, and 90-series&#39; firming and closing arms, with considerably more space afforded for the boot and tube assembly described and depicted in the &#39;594 patent. And, again, the rearward lower portion of the boot in Wendling &#39;594 fails to create sufficient enclosure to direct the great majority of seeds into the bottom of the furrow. 
       SUMMARY OF THE INVENTION 
       [0015]    After extensive field testing, the Applicant developed a seed boot and tube configuration for the John Deere 60- and 90-series opener assemblies that allows the tube to be oriented much more vertically (to the extent of angled forward at the bottom end) with the tube passing behind the opener disc&#39;s hub, and with a seed boot that stays entirely in the shadow of the opener disc (entirely within the furrow cut), thereby allowing the boot to extend considerably below the soil surface without imposing additional draft or down-force requirement on the drill or openers. Because the boot remains within the shadow of the opener disc, the wear on the boot and its attachment point (including the leaf spring) are substantially reduced as compared to the OEM design. 
         [0016]    Because the Deere 60- and 90-series design had a trajectory of seed delivery that was rearward at 45 degrees from vertical, and because the boot did not extend into the furrow, the wear occurring around the attachment bolt allowed the boot to tip even more horizontally when dragging in the soil, thereby causing still more seeds to be directed out of the furrow. Wear at the attachment bolt is far less critical for Applicant&#39;s boot, because the seed delivery tube is oriented slightly forward instead of rearward, because the tube is independent of the boot, and because the Applicant&#39;s boot extends significantly below the soil surface during normal operation. These attributes of the Applicant&#39;s invention ensure a high percentage of properly placed seeds regardless of wear at the boot&#39;s attaching bolt. 
         [0017]    Field testing has also shown the Applicant&#39;s boot to have significantly fewer problems with mud blockages as compared to the OEM design, presumably due to greater clearances in areas that typically gather mud from the opener disc, as well as the boot&#39;s narrower profile (i.e., remaining entirely in the shadow of the opener disc). The more vertical orientation of Applicant&#39;s seed delivery tube has further advantages in the reduced likelihood of seed or fertilizers failing to flow, as well as a more direct path with fewer obstructions to permit high product delivery rates, to allow large seeds to pass easily, and to facilit ate clean-out should an obstruction (e.g., a fertilizer clump) occur. 
         [0018]    Applicant&#39;s boot is attached directly to the opener subframe and is completely independent of the tube, which allows for easier installation and adjustment as well as reducing the stress imposed on the seed tube and its mounting points. The boot is attached via a single bolt with limited degrees of rotatable movement allowed about the axis of that bolt. The limited rotatable movement of the boot allows the boot to self-align against the opener disc. The boot is biased toward the opener disc by a leaf spring (the leaf spring and bolt are original equipment from the Deere 60- and 90-series opener assemblies). 
         [0019]    Because the boot is completely independent of the tube and not in any way constrained in its movement towards the opener disc during its normal wear life, no issue is presented with the boot failing to return to its proper operating position if deflected, such as by the Deere 60- and 90-series opener&#39;s firming wheel coming to rest on the boot when the opener assembly is lifted clear of the soil, or during maintenance or field operation. The seed tube is installed easily onto the opener subframe using existing features and without weakening the subframe with cutting or drilling additional holes or doing any welding. The seed tube can be easily removed for servicing the other components of the opener assembly. 
         [0020]    A seed-bounce flap at the rear of the boot ensures that seeds do not follow the rear edge of the opener disc upward during its rotation, as well as further directing the seeds into the bottom of the furrow. The flap is oriented essentially vertically, and completely covers the rear aperture of the chamber that is created by the opener disc and the boot so that an extremely high percentage of seeds is funneled into the bottom of the furrow, i.e., gaps at the rear of the boot are essentially eliminated. 
         [0021]    Applicant&#39;s seed boot is formed of sheet metal or similar material, and may be formed of abrasion-resistant high-carbon steel (e.g., AR 400 plate) or hard-surfaced on its lower edge to inhibit wear by the soil when seeding on contours, or when seeding on slopes sufficient to cause the opener discs to slightly mistrack such that the boot&#39;s lower edge abrades significantly against the furrow sidewall. In one variation of Applicant&#39;s invention, the OEM firming wheel arm is replaced with one that is functionally 1.5 inches longer and with a protrusion such that when the opener assembly is raised the firming wheel arm strikes the upper rearward corner of the boot, preventing the firming wheel itself from contacting the rear of the boot, which has numerous advantages. 
         [0022]    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 an 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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The present invention will become more clearly appreciated as the disclosure of the invention is made with reference to the accompanying drawings. In  FIGS. 1 to 4  as well as  FIGS. 6 to 8 , the opener assemblies are depicted as right-handed opener assemblies, although both right-hand and left-hand versions are available which are mirror images of each other. In the drawings: 
           [0024]      FIG. 1  is a cross-sectional view of the furrow and prior art seed boot, as viewed from the soil surface looking along the direction of travel of the opener assembly when the opener assembly is viewed from behind. 
           [0025]      FIG. 2  is a cross-sectional view of the furrow and a seed boot and tube according to the present invention, as viewed from the soil surface looking along the direction of travel of the opener assembly when viewed from behind. 
           [0026]      FIG. 3  is an exploded-perspective view of the drill opener assembly and prior art seed boot, as viewed from an elevated perspective slightly towards the rear and from beyond the right-hand side of the opener assembly itself. 
           [0027]      FIG. 4  is an exploded-perspective view of the drill opener unit together with a seed boot and tube according to the present invention, as viewed from an elevated perspective to the rear and from beyond the right-hand side of the opener assembly. 
           [0028]      FIG. 5  is a cross-sectional view of the attachment point of the seed tube according to the present invention. 
           [0029]      FIG. 6  is a cross-sectional view of the furrow and a seed boot and tube according to the present invention, as viewed from the soil surface looking along the direction of travel of the opener assembly when viewed from behind; it is the same view as  FIG. 2  but enlarged. 
           [0030]      FIG. 7  is a cross-sectional view of the furrow and a seed boot and tube according to the present invention, as viewed from the soil surface looking perpendicular to the direction of travel of the opener assembly. 
           [0031]      FIG. 8  is a cross-sectional view of the furrow and a seed boot and tube according to a variation of the present invention, as viewed from the soil surface looking perpendicular to the direction of travel of the opener assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    An improved seed directing tube and boot for agricultural seeders according to preferred embodiments of the present invention will now be described in detail by reference to  FIGS. 1 to 8  of the accompanying drawings. 
         [0033]      FIG. 1  is a cross-sectional view of the furrow-forming and seed-directing components of a common no-till drill opener assembly, the Deere 60 &amp; 90-series. The view depicted is from the soil surface looking along the direction of travel of the opener assembly when viewed from behind, taking into account the slight angle of the blade to the direction of travel. A plurality of opener assemblies are attached to a rockshaft (not shown) which is itself attached to a toolbar (not shown) for purposes of field operation in which the opener assemblies are drawn along the soil for placing seeds therein. While being pulled forward, pressure (down-force) is applied to the opener assembly via a large coil spring (not shown), which causes the opener disc  24  to rotate on its hub  23  about an axis and to penetrate the soil  12  with the penetration being limited by either the gauge wheel  20  or the amount of down-force available. The opener subframe (shown in  FIG. 3 ) causes the opener disc  24  to operate at a slight angle to the direction of travel, which causes soil  12  at the rearward edge of the opener disc  24  to move towards the gauge-wheel  20  side of the opener disc  24  thus creating an open furrow. The opener subframe also causes the opener disc  24  to operate at a slight departure from dimension ‘A,’ with dimension ‘A’ being defined as perpendicular to the soil  12  and nearby terrain. If the soil  12  and nearby terrain are exactly horizontal, then dimension ‘A’ is exactly vertical (“nearby terrain” is important because the toolbar&#39;s orientation is determined by the interaction of the toolbar&#39;s transport wheels against the topography being covered by the drill). The opener disc  24  operates in dimension ‘B,’ which is a slight departure from dimension ‘A’ so that the upper edge of the opener disc  24  is tilted towards the gauge-wheel  20  side of the opener assembly. 
         [0034]      FIG. 1  is looking along the soil surface and along the path of the opener disc  24 , which is traveling away from the viewer. The prior art seed boot  55  is relatively wide and has a lower edge  55 J that protrudes significantly beyond the cut of the opener disc  24 . Because of the resistance of the soil  12 , especially in no-till conditions, it is quite difficult to operate the lower edge  55 J much below the soil surface. 
         [0035]      FIG. 2  is the same view as in  FIG. 1 , except that a seed boot  70  and seed tube&#39;s lower portion  80 L according to the present invention are depicted (dimensions ‘A’ and ‘B,’ the soil  12 , and the opener components  20 ,  23 , and  24  are the same as in  FIG. 1 ). The seed boot  70  is arranged to hold and prevent loose soil adjacent to and/or comprising the side of the furrow from falling into the furrow in advance of the seed (not shown) being deposited in the furrow. The seed boot  70  has a first portion for attaching the boot  70  to the opener subframe  26  at a location above and forward of the hub  23  of the opener disc  24 . A second portion of the seed boot  70  comprises a forward edge  70 B that fits snugly against the opener disc  24  and functions as a scraper edge for contacting and scraping the side of the opener disc  24 . 
         [0036]    A third portion of the seed boot  70  forms an enclosure between the boot  70  and the opener disc  24  for guiding seeds into position in the furrow created by the opener disc  24 . The third portion includes a primary wall  70 A spaced apart laterally from the opener disc  24 , and a rear wall comprising an end-cap  70 V that extends between the primary wall  70 A and the opener disc  24 . The enclosure formed between the boot  70  and the opener disc  24  is below and rearward of the hub  23  of the opener disc  24 . The rear wall of the enclosure also comprises a flexible but resilient seed bounce flap  72  (shown in  FIGS. 6 to 8 ) that extends downwardly from the end-cap  70 V. A lower edge  70 J of the boot  70  stays entirely within the cut furrow created by the opener disc  24  in the soil  12 . The upper-rearward portion  70 P and the end-cap  70 V of the third portion of the seed boot  70  are flared to accommodate the seed tube&#39;s lower end  80 L without excessively constricting the width of the tube&#39;s lower end  80 L. 
         [0037]      FIG. 3  is an exploded view from a side-elevational perspective of the prior art seed boot  55  and the opener subframe  26  to which it attaches. The boot  55  is held from its upper end by a single bolt  31  extending in a longitudinal direction relative to a direction of travel of the opener assembly. The bolt  31  passes through holes in the boot&#39;s ears  55 C, which overlap the subframe ears  26 A. The bolt  31  is secured by a locknut (not shown) threaded onto the bolt  31 . A leaf spring  35  is contained by the ears  26 A, the bolt  31 , and by ridges (not shown) along one side of the boot  55  and on the subframe  26  (immediately below the ears  26 A in both cases). The boot  55  can rotate a few degrees on the axis of the bolt  31 , with the one side of the boot  55  being biased against the opener disc  24  by the force exerted by the leaf spring  35 . At the rear of the boot  55 , a seed bounce flap  58  can be slid into a groove and secured by a screw (depicted but not labeled), with the flap  58  protruding downward and rearward at about a 45-degree angle to the direction of travel (indicated by the wide arrow on the right-hand side of the  FIG. 3 ). Other components labeled in  FIG. 3  are for reference only, and will be described in detail in the discussion of  FIG. 4 . 
         [0038]      FIG. 4  is an exploded view from a side-elevational perspective of the present invention and the opener subframe  26  to which it attaches. The boot  70  is held from its upper forward end by a single bolt  31  passing through the holes in the boot&#39;s ears  70 C which overlap the subframe ears  26 A, and secured by a locknut (not shown) threaded onto the bolt  31 . A leaf spring  35  is contained by the ears  26 A, the bolt  31 , and by ridges (not shown) along one side of the boot  70  and on the subframe  26  (immediately below the ears  26 A in both cases). The boot  70  can rotate a few degrees on the axis of the bolt  31 , with the boot&#39;s forward edge  70 B being held against the opener disc  24  from the force exerted by the leaf spring  35 . 
         [0039]    The rearward portion of the boot  70  culminates in the end-cap  70 V, which extends from the primary wall  70 A towards the opener disc  24  to create the enclosure for receiving the lower end of the seed tube  80  and for guiding seeds into position in the furrow upon exiting the lower end  80 L of the seed tube. The boot&#39;s end-cap  70 V includes a hole for attaching the seed bounce flap  72  via a bolt  73  ( FIG. 7 ) such that the flap  72  is oriented essentially vertically but allowed to bend rearward at its lower edge during field operation. 
         [0040]    The flap  72  is essentially perpendicular to the plane of the opener disc  24  with one lateral edge of the flap  72  abutting the opener disc  24 , while the boot&#39;s metal end-cap  70 V has an edge that terminates just prior to contacting the opener disc. The boot&#39;s upper-rearward portion  70 P as well as end-cap  70 V are flared away from the opener disc  24  to accommodate the tube&#39;s lower end  80 L. The lower end  80 L is elliptical in cross-section, with a smaller dimension in a lateral direction than in a longitudinal direction, to occupy less lateral space in passing the constrictions among the opener components such as the firming wheel pivot bolt (not shown), as well as requiring less flaring of the boot portion  70 P and the end-cap  70 V. 
         [0041]    The lower end  80 L of the seed tube  80  extends into the enclosure created by the seed boot  70 . An upper end of the seed tube  80  is positioned to receive seeds from a metering mechanism (not shown) attached to the seed supply tank (not shown). The seed tube  80  is secured by an S-shaped bracket  80 N extending laterally and rearwardly from the tube  80 , with a hole  80 R in the inner rearward portion of the bracket  80 N. The bracket  80 N is secured by passing a bolt  41 ′ through the hole  80 R. The bolt  41 ′ is slightly longer than the OEM bolt  41 , both of which are employed to pivotally mount the closing wheel arm  39  to a socket  26 E formed in the casting of the opener subframe  26 . The seed tube  80  is thus attached to the opener subframe  26  independently of the boot  70  so that the boot  70  can move independently with respect to the seed tube  80 . 
         [0042]    Because of the relatively rigid nature of the tube  80  and the bracket  80 N in relation to opener subframe  26 , and the reasonably tight fit of the hole  80 R onto a sleeve area machined into the nut  47  (see  FIG. 5  for clear depiction), the tube&#39;s lower end  80 L is stabilized in position so as generally not to laterally contact either the opener disc  24  or the flared upper portion  70 P of the boot  70 . Alternatively, the hole  80 R may be constructed so as to be sufficiently loose that boot  70  merely deflects the tube&#39;s lower end  80 L towards the blade, since minor wear on this side of the tube&#39;s lower end  80 L is not detrimental to performance. The tube  80  is prevented from rotating rearward at its lower end  80 L by a portion of the bracket  80 N coming into contact with the area  26 H of the subframe  26 . 
         [0043]    Once the tube  80  is installed, the lower end  80 L of the tube  80  can rotate forward only about 0.5 to 0.75-inch before contacting the hub  23 . The tube  80  can be secured away from the hub  23  with a specially formed clasp (not shown) of spring steel, or similar means. Alternatively, the tube  80  may be allowed to rotate forward until contacting the hub  23 , being allowed to rub against the hub  23  via a special wear pad (not shown) attached to the tube  80  in the appropriate location. Other components labeled in  FIG. 4  are for reference only, and will be described in detail in the discussion of  FIG. 5 . 
         [0044]      FIG. 5  is a cross-sectional view of the closing arm assembly for the Deere 60 &amp; 90-series drill opener assembly. The closing arm  39  is pivotally connected to the opener subframe  26  by the bolt  41 ′, which (in conjunction with the sleeve  43 ) provides a pivot structure for allowing the closing arm  39  to rotatably move independently of the subframe  26 . The bolt  41 ′ also serves as the attachment point for the bracket  80 N of the seed tube  80 . The bolt  41 ′ extends through the housing  26 E of the opener subframe  26  and has the closing arm  39  attached on one side of the housing  26 E of the subframe  26 , and the bracket  80 N attached on the other side of the housing  26 E. The original bolt  41  (see  FIG. 3 ) that passes through the closing arm  39  and the tubular sleeve  43  has been replaced with a bolt  41 ′ that is approximately 0.5 inch longer. 
         [0045]    The sleeve  43  fits inside a pair of sleeves  42  that have been pressed into the cast housing  26 E, with sufficient clearance that the periphery of the sleeve  43  can rotatably move inside the sleeves  42 , with this rotatable movement further accommodated by the sleeve  43  being slightly longer than the axial length of the bore in housing  26 E. Washer  44  contains or “sandwiches” the sleeve  43  against the arm  39  as the locknut  85  is threaded and tightened. A special locknut  47  has been fabricated to include a reduced-diameter bushing area along part of its length. The seed tube bracket  80 N is then installed with the hole  80 R over the bolt  41 ′, and the special locknut  47  is threaded into place with the reduced-diameter bushing area fitting inside the hole  80 R. The tube  80  is trapped or contained when the special locknut  47  is tightened, although the clearance between the hole  80 R and the bushing area of the special locknut  47  permits the tube  80  to be isolated from the rotational movement of the bolt  41 ′ and closing arm  39  during field operation. The closing wheel (not shown) will follow undulations in the topography and cause back-and-forth rotation of the bolt  41 ′ as the arm  39  moves up and down, without causing the seed tube  80  to move. 
         [0046]      FIG. 6  is an enlarged view of  FIG. 2  from the same perspective and with all parts and labels identical to  FIG. 2 , except that the seed bounce flap  72  is depicted (hashed lines), which would typically be flexing towards the direction of the viewer due to drag exerted on the lower end of the flap  72  by the soil comprising the bottom of the furrow. One lateral edge of the flap  72  fits flush against the planar side of the opener disc  24 , while the other lateral edge of the flap  72  fits closely against the primary wall  70 A of the boot  70 , thereby creating a chamber or enclosure for funneling seeds through the enclosure and into the bottom of the furrow. The flap  72  operates in approximately the same plane as the boot&#39;s end-cap  70 V. The flap  72  is attached to the boot&#39;s end-cap  70 V by means of a bolt  73 ′ or similar fastener. The flap  72  can be made of nylon, polyethylene, UHMW plastic, or similar material that has flexing capability but some resilience of shape such that it can bend to clear obstacles but then return to its previous location to guide seeds (not shown) into position and to prevent seeds from following the opener disc  24  as it rotates upward. 
         [0047]      FIG. 7  is a cross-sectional side-view of the invention. The flap  72  is secured to the boot&#39;s end-cap  70 V by means of a counter-sunk bolt  73 . The furrow bottom  13  is the depth cut by the opener disc  24 , upon which the lower end of the flap  72  may drag, thereby causing minor arching of the flap  72 . It is considered desirable that the flap  72  extend as close to the furrow bottom  13  as feasible, and that the flap  72  has its lateral lower edges narrowing (tapering) to match the shape of the furrow being cut by the opener disc  24  as depicted in  FIG. 6 . 
         [0048]      FIG. 8  is from the same perspective as  FIG. 7 , but with  FIG. 8  depicting a variation of the invention whereby the shape of the boot  70  and the end-cap  70 V are altered such that the flap  72  is now attached to an area that is inclined slightly from vertical. This variation reduces the arching of the flap  72  as depicted in  FIG. 7 , thereby reducing stress on the flap  72  and reducing breakage of the flap  72  during field operation. The angle depicted in  FIG. 8  also provides better ability of the flap  72  to shed mud or other debris that occasionally is encountered by the flap  72 . 
         [0049]    Also shown in  FIG. 8  is another aspect of the invention wherein firming wheel arm  33 ′ replaces the original firming wheel arm (not shown). The firming wheel arm  33 ′ differs from the original firming arm in being approximately 1.5 inches longer, and having a protrusion  33 Q. When drill openers are raised for transport or turning in the field, previously the original firming wheel arm (not shown) was stopped in its downward travel when the firming wheel (not shown) came to rest on the rear portion of the original boot  55 . Occasionally this would cause damage to the boot  55 , as well as wearing both the boot  55  and the firming wheel (not shown) due to the sudden and repeated arresting of the firming wheel&#39;s rotation. 
         [0050]    The protrusion  33 Q of the replacement firming arm  33 ′ functions as an abutment for abutting a rear portion of the boot  70  to limit downward movement of the firming arm  33 ′. The geometry of the protrusion  33 Q is such that contact is made with an upper rearward boot corner  70 S of the boot  70  to halt downward motion of the firming arm  33 ′. Thus, the downward motion of the firming arm  33 ′ is halted prior to the firming wheel contacting the seed boot  70  at the lower part of the end-cap  70 V. This prevents damage to the firming wheel and the end-cap  70 V, and eliminates the need for a smooth surface on the rearward edge of the boot end-cap  70 V to minimize such damage. This allows the bolt  73 ′ to have a typical hexagonal head without the need to be countersunk. The added length of the firming arm  33 ′ also improves clearance between the firming wheel (not shown) and the rearward edge of boot  70 , which improves the ability of the firming arm  33 ′ and firming wheel to follow soil undulations. 
         [0051]    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.