Abstract:
A seed metering system, for use on a row crop planter, selects individual seeds from a seed reservoir and dispenses the seeds singularly at a controlled rate. A direct drive seed metering system includes a seed disc having a plurality of suction apertures with a recessed pocket adjacent to an aperture. The recessed pockets act to agitate seeds in the seed reservoir and to direct seed flow towards the apertures. A seed path relief system provides for allowing the placement of the seeds such that they are released from an outer edge of the seed disc. An adjustable seed singulator is mounted adjacent to the face of the seed disc where inner and outer blades are adjusted radially to compensate for the singulation of various seed sizes and shapes. The seed disc is driven via engagement of an internal gear with the external gear of an independent drive motor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Continuation application of U.S. Ser. No. 13/829,726, filed Mar. 14, 2013, which claims priority to Provisional Application U.S. Ser. No. 61/717,384, filed on Oct. 23, 2012, all of which are herein incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to mechanisms used in agricultural planting machines for selecting and dispensing individual seeds. More particularly, but not exclusively, the invention relates to air seed meters used to meter seeds from a row unit on agricultural row crop planters and seeders. 
       BACKGROUND OF THE INVENTION 
       [0003]    An agricultural row crop planter is a machine built for precisely distributing seed into the ground. The row crop planter generally includes a horizontal toolbar fixed to a hitch assembly for towing behind a tractor. Row units are mounted to the toolbar. In different configurations, seed may be stored at individual hoppers on each row unit, or it may be maintained in a central hopper and delivered to the row units on an as needed basis. The row units include ground-working tools for opening and closing a seed furrow, and a seed metering system for distributing seed to the seed furrow. 
         [0004]    In its most basic form, the seed meter includes a housing and a seed disc. The housing is constructed such that it creates a reservoir to hold a seed pool. The seed disc resides within the housing and rotates about a generally horizontal central axis. As the seed disc rotates, it passes through the seed pool where it picks up individual seeds. The seeds are subsequently dispensed into a seed chute where they drop into the seed furrow. 
         [0005]    Early seed meters were comprised of mechanical means of singulating seeds. These meters were constructed such that fingers on the face of the seed disc gripped seeds as they passed through the seed pool, subsequently releasing those seeds as they passed over the seed chute. Although these mechanical seed meters are effective, they are limited in their ability to assure singulation of seeds and are prone to dispensing duplicates (i.e., multiple seeds) and/or failing to dispense at all (i.e., skips or misses). Other mechanical meters use cells in conjunction with brushes to trap seeds within the cavity and release them over the seed chute. 
         [0006]    Systems that are more recent include an air seed meter, e.g., vacuum or positive pressure meters, wherein the mechanical fingers have been replaced by a disc with apertures. A pressure differential is formed across opposite sides of the seed disc, which generates a suction force at the seed cell apertures. As unobstructed seed cells pass through the seed pool, seeds are drawn onto or against the seed cells and remain thereon until the seed cell passes through a region of the housing with a reduced pressure differential. To create this reduced pressure differential region, generally the “vacuum” (i.e., lower pressure) side of the seed disc is exposed to air pressure near, but not always at, atmospheric levels. At this point, seeds are released from the seed cell of the seed disc and into the seed chute. Compared to mechanical meters, air seed meters promote improved singulation across a wider range of speeds. A problem that exists with an air seed meter is that it can be difficult for the suction (negative) force of the seed cell to draw seeds from a stagnant seed pool. Another problem with air seed meters, and specifically the seed disc, is that seeds not released at or near the edge of the seed disc are susceptible to increased ricochet or bounce, thereby negatively impacting seed spacing. For those air seed meters that do release seeds from at or near edge of the seed disc, seeds are sometimes knocked free of the cells on the seed disc by the seed meter housing sidewall because of the close proximity of the housing sidewall to the cell. 
         [0007]    Therefore, there is a need in the art for an improved seed metering system that improves upon attaching seed from the seed pool to the seed disc. There is also a need in the art for a seed meter that retains the advantage of releasing seed from at or near the edge of the seed disk, but yet reduces the likelihood of unintentionally bumping the seed from the disc during rotation. 
         [0008]    Seed spacing in the seed furrow is controlled by varying the rotational speed of the seed disc. Most commonly, seed disc rotation is driven by connection to a common driveshaft. The driveshaft runs horizontally along the length of the toolbar to connect to each row unit, and is driven by a single motor or a ground contact wheel. In this configuration, the planting rate can be adjusted for all row units uniformly by adjusting the rotational speed of the common drive shaft. This can be a tedious task, and an operator is unlikely to adjust the gear ratio as often as necessary to maximize yields. Generally, an optimal overall rate for a given acreage will be selected prior to planting and will be maintained at that rate regardless of soil conditions. Whether using a mechanical or vacuum style seed disc, the seed disc is installed inside of the seed meter using independent fasteners and requires the use of tools to facilitate changing the disc. For example, if a farmer uses the same planter to plant corn and soybeans, he would use a different disc for the respective seed types. With planters continuing to grow in size, and more row units being added, the task of changing seed discs using independent fasteners and tools adds unnecessary burden to changing out seed discs. 
         [0009]    There is thus a need in the art for a method and apparatus for changing the seeding rate of a seed meter to account for varying conditions, while also providing an easy to change or install method for removing and inserting a seed disc of the seed meter and rigidly retaining that seed disc within the seed meter housing. 
         [0010]    As the art of planting progresses, emphasis on the ability of a seed metering system to accurately and consistently distribute seeds to the seed bed grows. Singulation of seeds by seed meters and spacing of seeds along the seed bed is critical in assuring that a farmer or operator is getting the maximum crop yield out of a given acreage of land. If seeds are located too closely together, or in duplicates, they will compete with each other for available nutrients and moisture in the soil, negatively impacting growth. If seeds are located too far apart, or skipped entirely, useful nutrients and moisture will go unused by the growing crops and the farmer will not realize full yield potential of the land. The increased use of GPS and computer software to generate yield maps has provided farmers the information necessary to determine optimal real time seed spacing for each row. 
         [0011]    Thus, there is also a need in the art for a seed meter that allows for quick and easy adjustment to adjust the spacing between seeds planted in a row. 
       SUMMARY OF THE INVENTION 
       [0012]    It is therefore a primary object, feature, and/or advantage of the present invention to improve on or overcome the deficiencies in the art. 
         [0013]    It is another object, feature, and/or advantage of the present invention to provide a seed metering system that allows independent control of the metering rate of each row unit of a row crop planter. 
         [0014]    It is yet another object, feature, and/or advantage of the present invention to provide a vacuum seed disc that disrupts the seed pool as it passes through, thus loosening the seeds and directing the seeds towards the suction in the seed cell. 
         [0015]    It is still another object, feature, and/or advantage of the present invention to reduce the likelihood that a seed drawn onto or against a seed cell can be knocked free of the seed cell as it passes by the adjacent housing wall. 
         [0016]    It is a further object, feature, and/or advantage of the present invention to provide a seed disc having a pocket for adhering a seed to the disc and for aid in delivering the seed to the soil. 
         [0017]    It is still a further object, feature, and/or advantage of the present invention to provide a seed disc that delivers seed from an outside edge of the disc. 
         [0018]    These and/or other objects, features, and advantages of the present invention will be apparent to those skilled in the art. The present invention is not to be limited to or by these objects, features and advantages. No single embodiment need provide each and every object, feature, or advantage. 
         [0019]    According to an aspect of the invention, an air seed meter is provided. The air seed meter includes a housing defining a seed reservoir, a discharge chute, and a vacuum chamber. A seed disc is mounted in said housing for rotation about an axis and having a plurality of seed cells spaced about the axis for retaining seeds, with the disc having channels adjacent to each respective seed cell. Each respective channel is substantially inside of the seed cells and forward of its corresponding seed cell with respect to the rotational direction of the disc. Each respective channel has a length greater than its width. Each respective channel is oriented on the seed disc such that the length of the channel is at an oblique angle to a radius line of its seed cell such that the inner forward corner of the channel leads the outer forward corner with respect to the direction of rotation. 
         [0020]    According to another aspect of the invention, a seed disc for use with an air seed meter of an agricultural implement is provided. The seed disc includes a cylindrical structure having first and second sides and containing a plurality of apertures therethrough. The apertures are arranged in a radial array a distance from the axis of the structure. Channels are arranged in a radial array about the axis of the seed disc on the first side of the structure such that a respective channel is substantially radially inward and forward of a corresponding aperture. A central cylindrical aperture is included for mounting the seed disc to the seed meter. 
         [0021]    According to another aspect of the invention, an air seed meter for an agricultural planter is provided. The air seed meter includes a seed disc housed between a seed meter housing and a vacuum housing. The seed disc comprises a substantially circular member having a first side adjacent the seed meter housing and a second side adjacent the vacuum housing, and a plurality of apertures through the disc and spaced radially a distance from the axis of the member. The first side of the circular member comprises a plurality of channels arranged in a radial array about the axis of the seed disc such that a respective channel is substantially radially inward and forward of a corresponding aperture. The channels are configured to move seed adjacent the channel and to an aperture for retention until release therefrom. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a perspective view of a conventional planter row unit with an air seed meter attached thereto. 
           [0023]      FIG. 2  is a side elevation view of the conventional row unit of  FIG. 1 . 
           [0024]      FIG. 3  is a perspective view of an embodiment of an air seed meter. 
           [0025]      FIG. 4  is a perspective view of an embodiment of an air seed meter, showing the opposite side of  FIG. 3 . 
           [0026]      FIG. 5  is a planar view of an embodiment of the interior of the housing of the seed meter according to the invention. 
           [0027]      FIG. 6  is a front planar view of an embodiment of the vacuum housing of the seed meter according to the invention. 
           [0028]      FIG. 7  is a rear elevation view of an embodiment of the interior of the vacuum housing of  FIG. 6 . 
           [0029]      FIG. 8  is a side elevation view of an embodiment of the vacuum side of the seed disc. 
           [0030]      FIG. 9  is sectional view of an embodiment of the seed disc of  FIG. 8 . 
           [0031]      FIG. 10  is a perspective view of an embodiment central hub for use with an air seed meter. 
           [0032]      FIG. 11  is another perspective view of an embodiment the central hub of  FIG. 10 , shown in operative relation to a seed disc. 
           [0033]      FIG. 12  is a perspective view of an embodiment of the reservoir side of the seed disc. 
           [0034]      FIG. 13  is an enlarged view of a portion of the seed disc of  FIG. 12 , showing the seed cells and seed channels. 
           [0035]      FIG. 14  is a perspective view of an embodiment of the seed disc of  FIG. 12  including a singulation mechanism in operative relationship. 
           [0036]      FIG. 15  is a perspective view of an embodiment of the singulation mechanism of  FIG. 11 . 
           [0037]      FIG. 15 a    is a perspective view of another embodiment of a singulation mechanism. 
           [0038]      FIG. 16  is a perspective view of an embodiment showing the face of the singulation mechanism&#39;s rotational adjustment. 
           [0039]      FIG. 17  is a view of an embodiment showing the singulation mechanism with the rotational adjustment removed. 
           [0040]      FIG. 18  is a front partial sectional view of an embodiment of the seed disc and a unique drive in operative relations with the housing and other seed meter components hidden for clarity. 
           [0041]      FIG. 19  is a cross-sectional perspective view of another embodiment of a seed meter. 
           [0042]      FIG. 20  is a side elevation view of the reservoir side of the seed disc in  FIG. 18   a.    
           [0043]      FIG. 21  is a perspective view of the vacuum side of the seed disc in  FIG. 18   a.    
           [0044]      FIG. 22  is a perspective view of the vacuum housing of the seed meter in  FIG. 18   a.    
           [0045]      FIGS. 23 a  and 23 b    are sectional perspective views of an embodiment of the interface between the seed disc and the seed meter housing. 
       
    
    
       [0046]    Before any independent features and embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0047]    Referring to  FIG. 1 , a conventional planter row unit  10  with an air seed meter  5  is shown. The row unit  10  and air seed meter  5 , as shown in  FIGS. 1 and 2 , is known in its general aspects to persons skilled in the art. The row unit  10  includes a U-bolt mount  11  for mounting the row unit  10  to a planter frame or tool bar (not shown), as it is sometimes called, which may be a steel tube of 5 by 7 inches (although other sizes are used). The mount  11  includes a faceplate  12 , which is used to mount left and right parallel linkages. Each linkage may be a four-bar linkage, such as the left one  14  shown in  FIG. 1 . It is noted that the opposite (right) linkage is generally a mirror image of the linkage  14  shown in  FIG. 1 . The double linkage is sometimes described as having upper parallel links and lower parallel links, and the rear ends of all four parallel links are pivotally mounted to the frame  15  of the row unit  10 . The frame  15  includes a support for an air seed meter  5  and seed hopper  16 , as well as a structure including a shank  17  for mounting a pair of ground-engaging gauge wheels  18 . The frame  15  is also mounted to a furrow-closing unit  19 , which includes a pair of inclined closing wheels  19   a ,  19   b . The row unit  10  also includes a pair of furrow opener discs  9 , as shown in  FIG. 2 . 
         [0048]      FIG. 3  and  FIG. 4  represent a seed meter  20  according to an exemplary embodiment of the invention. The seed meter  20  of  FIG. 3  and  FIG. 4  includes a seed meter housing  21 , which contains the seed disc  22  and central hub  25 . The seed disc  22  and central hub  25  are exposed for illustration purposes, but would normally be concealed behind a vacuum housing  200  attached to the seed meter housing  21 . The vacuum housing  200 , shown in  FIG. 6  and  FIG. 7 , also includes a vacuum inlet  202  for a vacuum or other air source (not shown), an aperture  204  to allow seed disc central hub  25  to pass through, and attachment means  206  (shown to be keyhole slots) at an outer area of the vacuum housing  200 . The seed meter housing  21  and the vacuum housing  200  may be molded, such that they comprise molded plastic or other rigid materials. 
         [0049]    Seed is conveyed into a reservoir  26  on the seed meter housing  21  via an input tube (not shown) or a seed hopper ( FIG. 1 ). Once in the reservoir  26 , the seed pools adjacent the seed disc  22  near the bottom or lower portion of the seed meter housing  21  and becomes attached to the seed disc  22  as the seed disc  22  is rotated by direct drive  27 . The interior of the seed meter housing  21  without the seed disc  22  is shown in  FIG. 5 , which also shows the location of the reservoir  26  inside the seed meter housing  21 . A door  167 , which may be slidable or otherwise movable, may be positioned adjacent the reservoir opening to provide access to the reservoir  26  to aid in emptying or cleaning out the reservoir  26 .  FIG. 5  also shows the location and configuration of a singulator  111 , which is used to prevent multiple seeds becoming attached at a single seed cell  54 . The singulator  111  is shown in  FIGS. 14-17 . Seeds are then released from the seed disc  22  as they transition through a zone  30  of the seed meter  20  having little to no pressure differential. Seeds are dropped into the seed chute  24 , which delivers them to the furrow. 
         [0050]    The vacuum housing  200 , as shown in  FIG. 6  and  FIG. 7 , includes a vacuum inlet  202 , which is connected to a vacuum source (not shown), such as a vacuum impeller, via vacuum hoses (not shown). The seed meter housing  21  includes a plurality of bosses  32  disposed along its periphery, as shown in  FIG. 3 . The plurality of bosses  32  are configured to extend through the attachment means  206  of the vacuum housing  200  to locate the vacuum housing and, after rotation by the user, restrain it in place against the seed meter housing  21 . The attachment means  206  of the vacuum housing  200  are shown to be keyhole slots, but any other configuration can be used. The vacuum housing  200  further includes a sealing member  208  fitted into a groove on the interior of the vacuum housing  200 . The sealing member  208  contacts the seed flange  51  of the vacuum side of the seed disc  22  (see, for example,  FIGS. 8 and 9 ) to define a vacuum chamber  210  in communication with the vacuum inlet  202 . The sealing member  208  is also surrounded by an annular rim  162  of the seed disc  22  to improve suction at the seed cells  54 . As seed cells  54  move into the vacuum chamber  210 , they are placed in fluid communication with the vacuum source. A plurality of apertures  211  in the chamber  210  provide for suction from the vacuum source along the length of the chamber  210 . 
         [0051]    Also mounted to the inside of the vacuum housing  200  is a remnant ejector  212  for the removal of seeds or seed remnants from a seed cell  54  after the seed cell passes the seed chute  24  and is no longer in communication with the vacuum chamber  210 . The remnant ejector  212  is housed within an ejector housing  215  formed integrally with the vacuum housing  200 . However, the ejector housing  215  may also be removable so as to allow different ejectors to be used according to different seed discs and seed types. The remnant ejector  212  interfaces with a series of seed cells  54  from the vacuum side of the seed disc (shown in  FIGS. 3 and 8 ). The remnant ejector  212  includes a rotatable wheel  214  with a plurality of punches  216  about its periphery to remove seeds, seed debris, or other remnants remaining in a seed cell  54  after it passes the seed chute  24 . The remnant ejector  212  is spring-biased towards the seed disc  22  and moves synchronously with the seed disc  22  as it is rotated, i.e., the rotation of the seed disc  22  rotates the wheel  214  of the remnant ejector  212 . Furthermore, the remnant ejector  212  is rotatable about legs  218  to allow the ejector to move relative to the biasing spring, which aids in pressing the punches  216  of the wheel  214  to remain biased against the seed cells  54  of the seed disc  22 . 
         [0052]      FIG. 8  illustrates the vacuum side of the seed disc  22 . The seed disc  22  is substantially cylindrical and has opposing sides—a vacuum side shown in  FIGS. 3 and 8 , and a reservoir side, which contacts a pool of seed ( FIG. 12 ). It should be noted that the “vacuum side” generally refers to the side of the disc  22  that will be adjacent the vacuum source. The seed disc  22  comprises a molded plastic or other rigid material. The seed disc  22  has a cross-sectional profile as shown in  FIG. 9 . The cross-sectional profile of the seed disc  22  shows at least two zones on the seed disc  22 . The first zone is a generally flat seed flange  51  located at or near the outer radius of the seed disc  22 . A series of seed cells  54  located at the seed flange  51  comprise apertures extending from the vacuum side to the reservoir side, and are spaced radially about the circumference of the seed disc, which is generally a circle. The aperture of the seed cells  54  may be larger on the vacuum side of the disc  22  and narrow through the disc  22  such that the negative pressure on the seed side of the disc  22  is increased. Alternatively, a single-sized aperture may form the seed cell  54 . The seed flange  51  also includes an annular rim  162  extending radially outward from the plurality of seed cells  54  and which will be described later in further detail. Although in the embodiment shown in  FIG. 8  a single seed cell circle is shown with seed cells  54  being positioned at an equal radius, one skilled in the art may also appreciate that seed cells could be staggered about multiple circles to create an alternating pattern. It should also be appreciated that the spacing and size of the seed cells  54  may be changed from the illustrated embodiments to accommodate different seed types and planting methods. The present seed disc and seed cells are not to be limited to the embodiments shown and described. 
         [0053]    A second zone  52  is shown by the cross-sectional profile of the seed disc  22 . The second zone is contoured and located radially inward of the seed flange  51 . The second zone  52  includes a cylindrical internal flange  55 . The internal flange  55  is formed substantially perpendicular to the seed flange  51  and is substantially concentric with the center axis of the seed disc  22 . The interior sidewall of the cylindrical interior flange  55  includes four keyways  53  running longitudinally through the interior flange  55  and spaced evenly about the inner circumference of the flange  55 . The cross-section of the keyways  53  is substantially similar to the external profile of the hub protrusions  61  as shown in  FIG. 10 . While four keyways are shown in the figures, it should be appreciated that generally any number of keyways are contemplated for use with the seed disc  22  of the exemplary embodiment. When more or less keyways are used with a seed disc, the keyways can be radially spaced around the axis of the disc, or can otherwise be positioned to align with at least as many hub protrusions  61  for connecting the hub to the seed disc. 
         [0054]    The seed disc  22  can be fixed within the seed meter  20  without the use of fasteners or tools by inserting the central hub  25  of the seed meter housing  21  through the aperture  56  created by the inner flange  55  of the seed disc  22 . The keyways  53  of the inner flange  55  are shaped and aligned at 90-degree intervals to receive the protrusions  71  of the hub  25  (see, e.g.,  FIG. 10 ). With the central hub  25  inserted through the inner flange  55 , the protrusions will emerge from the keyways  53 . The hub  25  can then be rotated in the direction shown by the embossed arrows  57  (see, e.g.,  FIG. 8 ), while the seed disc  22  is restrained, such that the protrusions  71  will engage recesses or notches  81  on the rim of the interior flange  55  of the seed disc  22 , as shown in  FIG. 11 . The seed disc  22  could also be rotated while the hub  25  is restrained to lock and unlock. The central hub  25  slidably mounts to a first end of a shaft  40  to fix the position of the seed disc  22  within the seed meter housing  21 . The central hub  25  is retained in place by an upper roll pin  42  passing through an aperture on the shaft  40  and lower dowel pin, located on the shaft  40 , which may otherwise be the protrusions  71  of the hub  25 . The second, opposite end of shaft  40  is rotatably and axially coupled to an integrated shaft bearing. The shaft bearing (not shown) may be a plain bearing, such as generally any cylindrical sleeve made of a low friction material, a rolling-element bearing, which uses spheres or small cylinders that rotate or roll between a shaft and the mating parts to reduce friction and allow much tighter mechanical tolerances, or a water pump-style bearing. The shaft bearing is positioned in a cavity  44 , as shown  FIG. 4 . It should be appreciated that when other numbers of keyways  53  are used to aid in attaching the seed disc  22  to the seed meter  20 , the keyways may be located at other angles, such that the disc  22  or hub  25  can be rotated more or less to engage the protrusions with the recesses. 
         [0055]    Turning now to the reservoir side of the seed disc  22 , which is shown in  FIG. 12 , a plurality of recesses or channels  91  are shown formed in the seed flange  51 . On the reservoir side of the seed disc  22 , the seed flange  51  includes a portion extending from the face of the disc  22  and including an inner lip  96  and an outer chamfer  94 . The outer chamfer  94  may be beveled or other angular in relation to the face of the seed disc  22 .  FIG. 13  shows an enlarged view of these recesses or channels  91 . A recess or channel  91  is present for and respectfully aligned to a seed cell  54 . The recess or channel  91  is positioned substantially forward of its corresponding seed cell  54  with respect to the rotational direction (as shown by the arrow  93  of  FIG. 12 ) of the seed disc  22  during operation and provides agitation of seed in a seed pool when the seed disc  22  is rotated. The channel  91  is oriented at an oblique angle with respect to the radius line that passes through the center of corresponding seed cell  54 . This angle directs seed radially outward and rearward with respect to the rotational direction  93  of the seed disc  22  during operation, such that seed is guided towards the seed cells  54 . The channels  91  as shown are substantially rectangular in shape, but could be also comprise an oval or any other shape that would aid in the directing of seed towards seed cells  54 . It should also be appreciated that the shape and configuration of the channels can aid in loosening seeds in the reservoir, while also guiding them towards the seed cells  54 . Furthermore, the channels or recesses include a ramped portion  97  generally adjacent the seed cell  54 , which is used to position the seed at the seed cell  54  during rotation of the seed disc  22 . 
         [0056]    Therefore, the channels  91  of the seed disc  22  provide numerous advantages. As the channels  91  are generally recessed areas separated by wall-like portions, they will increase agitation of the seed pool to promote the movement of the seeds from the seed pool. The recessed channels  91  will also provide a direct path from the seed pool to the seed cells  54 , which will promote good adhesion between the seed and the seed disc  22  at the seed cells  54 . This will aid in increasing the accuracy of the seed meter by increasing the likelihood that a seed will be adhered to the seed cell  54 . As the channels  91  are formed integrally with the seed disc  22 , they can be configured and numbered to match generally any number of seed cells  54  and can be oriented or sized to best match with any type of seed. In the alternative, one single channel  91  size and orientation may be configured such that it is usable with all types of seed. 
         [0057]    In addition, the reservoir side of the seed disc  22  will include an outer chamfer  94  and an extension surface  95 , which extends generally from the outer chamfer  94  to the annular lip  162  on the periphery of the seed disc  22 . The outer chamfer  94  essentially forms a “false edge” of the seed disc  22 , to better position the seed at or near the edge for better consistency during release of the seed into the chute  24 . During rotation of the seed disc  22 , and after the seeds have adhered to the seed cells  54 , the disc  22  will continue to rotate until a seed passes the zone  30  of the seed meter  20  with little to no pressure differential. At this location, the outer chamfer  94  will be directly adjacent the outer wall of the seed meter housing  21 , which positions the seed and seed cell  54  at the false “outer edge” of the seed disc  22 . Thus, the seed will become disengaged from the seed cell at the outer edge, which will decrease the likelihood of ricochet or bounce as the seed passes through the chute  24 , thereby increasing seed spacing consistency. The length of the extension surface  95  will vary based upon factors such as the amount of offset  161 , the type of seed, how close the seed cells  54  need to be to the “edge”, as well as other factors. The creation of the “false edge” provides for the seed to be released at or near the “edge” of the seed disc  22 , while still providing enough suction as the disc  22  passes adjacent the seed pool, as will be discussed below. 
         [0058]    In situations where duplicate seeds may be drawn onto or against a single seed cell  54 , a singulator  111 , such as that shown in  FIGS. 5, 14, 15, and 17  can be used. The singulator  111  is configured to remove the excess seed(s) from the seed cell. The singulator  111  is mounted at and operatively connected to the seed meter housing  21  such that a first blade  112  (shown most clearly in  FIG. 17 ) and a second blade  113  is adjacent to the reservoir side face of the seed flange  51  and the seed cells  54 . The blades are spaced from the face of the seed disc  22 , as well as the flange  51  and seed cells  54 . The blades  112 ,  113  may be configured such that they are on opposite sides of the seed cell circle. The singulator  111  is biased towards the axis of the seed disc  22  and/or seed meter housing  21 . The biasing towards the axis of the seed disc  22  and/or seed meter housing  21  may be provided by a spring, gravity, or other tension member, such as by attaching the singulator  111  by a wire to the seed meter housing  21 . The singulator  111  is configured to have a fixed, curved rim portion  119  that at least partially surrounds the annular rim  162  of the seed disc, which aids in positioning the singulator  111  adjacent the seed cells  54 . 
         [0059]    The first blade  112  is positioned adjacent to the backside of the curved rim  119 , i.e., the side furthest from the seed disc  22 , and radially outward of the seed cell  54  circle. The first blade  112  includes an inner edge with a first set of ramps  115  and a generally curved profile similar to the circumference of the seed cell circle. Biasing the singulator  111 , including first blade  112 , generally inward towards the axis, aids in keeping the blade  112 , and thus, the ramps  115 , at the outer edge of the seed disc  22  to position the blade  112  and ramps  115  adjacent an outer area of the seed cells  54 . This aids in removing additional seeds at the seed cells  54  so that one seed is positioned at a seed cell  54 . 
         [0060]    The second blade  113  is spaced from the first blade  112  and is positioned radially inward of the seed cell circle  54 . The second blade  113  includes an inner edge (closest to the seed cell circle) with a second set of ramps  116 . It should be appreciated that the singulator  111  could have other ramp configurations for different seed types and the profile of the blades are not to be limiting to the exemplary embodiment. For example, smaller seeds such as a soybean seed may need less aggressive singulation and, therefore, fewer or smaller ramps can be used than for larger seeds like corn. It should also be appreciated that first blade  112  and second blade  113  could be comprised of a plurality of individual ramp assemblies, capable of moving independent of or in relationship with one another. For instance, a first ramp on first blade  112  could move independent of or in relationship with a second ramp on first blade  112 , or a first ramp on first blade  112  could move independent of or in relationship with a first ramp on second blade  113 . 
         [0061]    The first blade  112  and second blade  113  are attached to first and second carriages,  121  and  122 . In addition, the first and second blades  112 ,  113  may be formed integrally with the carriages  121 ,  122 . The blades  112 ,  113  may be attached to the carriages  121 ,  122  such that they can be replaced after wear and tear, or due to a change in the type of seed being using with the system. Therefore, screws, or other temporary attachments may be used to at least temporarily attach the blades to the carriages. 
         [0062]    The first and second carriages,  121  and  122 , are manipulated via a rotary adjustment  114  in a manner such that the first blade  112  adjusts radially outward as the second blade  113  simultaneously adjusts radially inward or vice versa, thus changing the width of the seed path between the first and second blades  112 ,  113  for the seed cells  54  to pass through. The second blade  113  is connected to the rotary adjustment  114  via a cam or other mechanism that converts the rotational movement of the rotary adjustment  114  to a translational movement of the first  112  and/or second blade  113 . Thus, the second blade  113  (and/or first blade  112 ) moves generally towards or away from the first blade  112  in a longitudinal manner as the rotary adjustment is rotated. For example, the blades  112 ,  113  may be slidably connected such that the blades slide along guides, slots, or notches in the singulator  111 . However, it is not required that both carriages, and thus, both blades move with rotation of the rotary adjustment  114 . For example, it is contemplated that only one of the blades move when the rotary adjustment  114  is rotated to either widen or narrow the distance between the blades, and thus, the ramps on the blades. Furthermore, the curved rim  119  remains fixed while the first blade  112  moves to ensure positioning of the singulator  111  adjacent the seed cells  54 . 
         [0063]    A wider seed path typically allows for less aggressive singulation, i.e., less contact by a ramp  115 ,  116  with a seed(s) in the seed cell  54 . A narrower seed path typically creates more aggressive singulation, i.e., more contact by a ramp  115 ,  116  of a seed(s) in a seed cell  54 . The level of aggressiveness is determined based on a number of factors, including, but not limited to, seed size, rate of seed dispensing, type of seed, and/or the amount of suction present at the seed cell  54 . However, the singulator  111  is generally configured such that only one seed is drawn onto or against the seed cell  54  and any other seeds drawn onto or against the seed cell  54  are knocked off into the seed pool. The slot  28  in the housing allows an operator to easily access the rotary adjustment  114 , so as to adjust the width of the seed path between the first and second blades  112 ,  113  without removal of any parts. This allows the singulator  111  to be used in the seed meter  20  with a variety of types of seeds, e.g. corn, bean, etc., while also allowing quick and easy adjustment for the width of the path between the blades. 
         [0064]      FIG. 16  illustrates a view of the face of the rotary adjustment  114 . On the face are cam grooves  131  and  132 . These grooves  131 ,  132  vary in radial distance from the center axis  134  of the rotary adjustment  114 . Rotating the rotary adjustment  114  causes the first and second carriages  121 ,  122  (and thus, first and second blades  112 ,  113 ) to move in a linear direction either toward or away from the axis of the seed disc  22 , which changes the width of the path between the blades  112 ,  113  such that the blades can be used with different types and sizes of seeds. With the carriages restricted to linear motion, the engagement of the carriage protrusions,  141  and  142 , with the cam grooves,  131  and  132 , causes the carriages to change position relative to the rotation of the rotary adjustment  114 . The carriages  121 ,  122 , and protrusions  141 ,  142  can be seen in  FIG. 17 . However, as noted above, when only one of the blades  112 ,  113  is to be moved, only one set of grooves can be included on the face of the rotary adjustment  114  such that rotation thereof causes the protrusion in engagement with the groove to move linearly. 
         [0065]    The singulator  111  can also be a removable cartridge from the seed meter housing  21  to allow the singulator  111  to be repaired, replaced, cleaned, adjusted, etc. The singulator  111  includes attachment means  117 , such as feet extending generally from the bottom side of the singulator  111 . The feet  117 , which are shown for exemplary purposes, are configured to fit into slots  118  (see  FIG. 5 ) formed integrally with or attached to the inside of the seed meter housing  21 . Therefore, to remove the singulator  111 , a set of snaps on the singulator are disengaged, allowing the singulator to be rotated and the feet  117  to remove from the slots  118  in the seed meter housing  21 , and removing the rotary adjustment  114  through an aperture in the seed meter housing  21 . To replace the singulator  111 , the feet  117  are positioned in the slots  118 , and the rotary adjustment  114  is positioned through the aperture in the seed meter housing  21  to provide access for a user to adjust the spacing between the first and second blades  112 ,  113 . Furthermore, any number or configuration of snaps or other members may be added to the singulator body and/or housing to aid in retaining the singulator in place in the seed meter housing  21 . 
         [0066]    In another embodiment of a singulator mechanism, which is shown generally in  FIG. 15 a   , the singulator  111  does not include a set of snaps and feet  117 , but instead is secured to and within the seed meter housing  21  by a tension member  120 , such as a flat spring. In this manner, the singulator  111  can be removed from the housing by sliding clips  120   a  upwardly and then towards the user with respect to boss  120   b . Singulator  111  can then be removed from the seed meter housing  21  for repair, replacement, cleaning and adjustment. In other embodiments using the tension member  120 , protrusions may extend from the interior of the seed meter housing  21 , with apertures of the tension member  120  simply snapping to or otherwise fitting on the protrusions to at least temporarily secure the singulator  111  to the seed meter housing  21 . 
         [0067]      FIG. 18  provides an illustration of the interaction between the unique drive  27  and the seed disc  22  according to an exemplary embodiment of the invention. A portion of the seed meter  20  has been sectioned away to show internal components of the assembly. As shown in  FIG. 18 , the unique drive  27  is mounted externally to the seed meter housing  21  such that an output shaft  154  of the drive  27  protrudes through at least a portion of the seed meter housing  21  perpendicular to and adjacent the face of the reservoir side of seed disc  22 . An external gear  153  is mounted on or otherwise forms a portion of the output shaft  154 . Integrally molded into, or attached to in some embodiments, the reservoir side of the seed disc  22  is an internal gear feature  152 . Said internal gear  152  and said external gear  153  are positioned such that their matching gear teeth engage each other. This engagement allows direct control of the rotational speed of the seed disc  22  via control of the unique drive&#39;s  27  rotational output speed of the output shaft  154 . In an exemplary embodiment, the unique drive  27  is powered by an electric motor  151 , but one skilled in the art may appreciate that the unique drive could also derive its power from a pneumatic or hydraulic rotary motor, as well as any other type of rotary motion, including but not limited to, mechanical, cable drive, or chain. 
         [0068]    In another embodiment of a seed meter, as shown in  FIG. 19 , the unique drive  27   a  is mounted externally to the vacuum housing  200   a  such that the output shaft  154   a  protrudes through the vacuum housing  200   a  substantially perpendicular to and adjacent the face of the vacuum side of the seed disc  22 . An external gear  153   a  is mounted on or otherwise forms a portion of the output shaft  154   a . Integrally molded into the vacuum side of the seed disc  22   a  is an internal gear feature  152   a . The internal gear feature  152   a  may also be a separate element that is attached to an internal ring or flange of the vacuum side of the seed disc  22   a . Said internal gear feature  152   a  and said external gear  153   a  are positioned such that their matching gear teeth engage each other such that the output of the unique drive  27   a  rotates the seed disc  22   a .  FIGS. 20-22  further depict the seed disc  22   a  and vacuum housing  200   a  of the modified embodiment. 
         [0069]    The control of the speed of the unique drive  27 ,  27   a , and thus seed disc  22 ,  22   a , allows for the spacing of the seeds during planting to be better controlled. As noted, the rotational velocity of the seed disc  22 ,  22   a  in relation to the speed of travel of the tractor or other equipment aids in controlling the distance between seeds in a row. Therefore, the addition of the unique drive  27 ,  27   a  allows an operator to control the distance by simply adjusting control of the drive  27 ,  27   a . For example, an operator in a tractor could adjust the rotational speed via remote or other control interface such that the distance between seeds could be adjusted during planting. This can result in significant time savings, as the operator does not have to stop planting to adjust seed rate of the meter, thus allowing a field to be efficiently planted with varied planting conditions. 
         [0070]    Referring to  FIGS. 23 a  and 23 b   , an enlarged and sectional view of the seed meter  20  is shown detailing the interface between the seed disc  22  and the seed meter housing  21 . In certain areas, an offset portion  161  of the outer sidewall  163  is provided to be eccentric with the outer circumference (e.g., annular rim  162 ) of the seed disc  22 . A relief member  165 , which is also shown in  FIG. 5 , covers the space created by the offset portion  161  between the seed cell  54  of the seed disc  22  and the bottom edge of outer sidewall  163 . For example, as shown in  FIG. 23 a   , the offset portion  161  is eccentric with the seed disc  22  at the loading zone  166 , i.e., the area of the seed meter  22  where the seed pools and is agitated prior to being drawn onto or against a seed cell  54 . The area created by offset portion  161  and covered by the relief member  165  gives the seed additional room to move about and be drawn onto or against the seed cell  54 , which reduces the likelihood of the seed being knocked free from the seed cell  54  by the seed meter housing  21  during rotation of the seed disc  22 . The relief member  165  also aids in orienting the seed in the seed cell  54  such that a greater surface area of the seed will fit in the cell  54  to provide the strongest suction on the seed at the cell  54 . 
         [0071]    The relief member  165  essentially creates a false outer wall of the seed meter housing  21 . As mentioned above and shown best in  FIGS. 12 and 13 , the reservoir side of the seed disc  22  will include an outer chamfer  94  and an extension  95  that ends at the annular rim  162  of the seed disc  22 . As mentioned above, the outer chamfer  94  and extension  95  creates a false edge for the seed disc  22 , which allows the seed cells  54  to be positioned generally at the outer edge of the false edge. While the false edge created by the outer chamfer  94  and extension  95  aids in releasing seed, they can make it difficult for the seed to attach to a seed cell  54  at the seed pool due to the decreased suction at the outer edge of the seed disc  22 . The offset portion  161  and relief member  165  counteract this by creating a “false wall”. The so-called false wall created by the relief member  165  will extend from the outer chamfer  94  to the outer wall of the seed meter housing  21 . The width of the false wall (relief member  165 ) will make it appear as though the seed is being attached at a location further inward on the seed disc  22 , with the relief member providing a barrier to create more suction at the seed cell  54  to increase the consistency of seed attaching to the seed cells  54 . The relief member  165  and offset  161  can extend to the entrance of the singulator  111 , which is used to ensure that only one seed is positioned at each seed cell  54 . 
         [0072]    An air seed meter for dispensing seed in a field has been provided. The exemplary embodiments shown and described contemplate numerous variations, options, and alternatives, and are not to be limited to the specific embodiments shown and described herein. For example, the improvements described herein are equally applicable to other meters, such as positive-air meters like that disclosed in U.S. Pat. No. 4,450,959 to Deckler, which is incorporated herein by reference in its entirety. The foregoing description has been presented for purposes of illustration and description, and is not intended to be exhaustive list or to limit the exemplary embodiment to precise forms disclosed. It is contemplated that other alternative processes obvious to those skilled in the art are considered to be included in the invention.