Abstract:
The present invention is directed to a planter with seed meters with accelerator wheel systems. Each accelerator wheel system receives singulated seeds from a respective seed meter and spaces the seeds with respect to each other to correct timing and thus spacing anomalies of seeds being released from seed disks of the seed meters at incorrect seed disk release events and to adjust the velocity of the seeds to correspond to planter travel speed for releasing the seeds to drop straight down onto the field, without a horizontal velocity. Spacing and timing is also improved by reducing delivery variation typically attributable to bounce down a seed tube by instead smoothly rotationally redirecting seeds from a generally downward delivery direction from a seed disk to a generally horizontal delivery direction out of the accelerator wheel system, opposite the tractor and implement travel direction.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to row-crop planters and, in particular, to planters with seed meters with accelerator wheel systems. 
       BACKGROUND OF THE INVENTION 
       [0002]    Modern farming practices strive to minimize operating expenses. One way of reducing operating expenses is to operate the farm equipment at relatively faster travel speeds, which reduces the amount of operating time to complete certain tasks. When operating equipment at faster travel speeds, it can be important to maintain the quality of operation that can be achieved while operating at relatively slower operating speeds. This can be especially difficult to accomplish during planting and seeding operations that require precise seed depth placement and spacing accuracy in order to maintain a good seed environment. Delivering singulated seeds at relatively faster equipment speeds can lead to seed tumble in the furrows or otherwise provide inconsistent seed spacing. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is directed to a planter with seed meters having accelerator wheel systems that mitigate seed tumble and improve seed spacing at relatively faster planter travel speeds. The accelerator wheel system corrects timing and thus spacing anomalies of seeds being released from seed disks of the seed meters at incorrect seed disk release event. This is done by catching all of the seeds from the seed disks, including any seeds mis-released from the seed disks, and properly spacing the seeds by moving and receiving them into equally spaced pockets of an accelerator wheel. Spacing and timing is also improved by reducing delivery variation typically attributable to bounce down a seed tube by smoothly rotationally redirecting seeds from a generally downward delivery direction from a seed disk to a generally horizontal delivery direction out of the accelerator wheel system, opposite the tractor and implement travel direction. Rotating the accelerator wheel releases the seeds from the accelerator wheel system at consistent release intervals. The accelerator wheel increases the velocity of the seeds to release the seeds from the accelerator wheel system with a horizontal velocity component that is the same as the travel speed of the planter. This provides a relative velocity of the released seeds with respect to the ground or field of approximately zero mph, substantially eliminating seed tumble during planting. 
         [0004]    According to another aspect of the invention, the velocity of the seeds in the accelerator wheel system is substantially increased compared to the velocity of the seeds in the seed meter. This may include increasing the velocity of the seeds in the accelerator wheel system by at least about five times, at least about eight times, or at least about ten times greater than that in the seed meter. 
         [0005]    According to another aspect of the invention, a planter is provided that includes a chassis towable behind a tractor through an agricultural field for planting seeds onto the field during a planting session. The planter moves through the field in a planter travel direction with a planter velocity (V Planter ). Multiple row segments are supported by the chassis. Each of the multiple row segments has a seed meter with a seed meter housing and is configured for singulating seeds for individual delivery into the seed trench. The seed meter releases the individual seeds out of a seed meter housing outlet, into an accelerator wheel system. The accelerator wheel system is configured to accelerate the individual seeds in and release the accelerated seeds into the seed trench. The seeds are released from the accelerator wheel system in a seed release direction that is substantially opposite the planter travel direction and with an accelerated seed release velocity (V Accelerated Seed Release ) corresponding to a velocity of the seeds released from the accelerator wheel system. The V Accelerated Seed Release  value includes a horizontal velocity component (V Accelerated Seed Release-Horizontal ) value corresponding to a horizontal component of the V Accelerated Seed Release  value and wherein the V Accelerated Seed Release-Horizontal  value is substantially equal to the V Planter  value. This provides a relative velocity of the released seeds with respect to the ground of approximately zero mph, substantially eliminating seed tumble during planting. 
         [0006]    According to another aspect of the invention, the seed meter has a seed disk rotating inside the seed meter housing. The seed disk conveys individual seeds through the seed meter housing for release out of an outlet of the housing and into the accelerator wheel system at a seed meter release velocity (V Seed Meter Release ). The accelerator wheel system further includes an accelerator wheel housing with an inlet aligned with or defined by a common passage of the seed meter housing outlet to receive the individual seeds from the seed meter. An accelerator wheel is arranged for rotation inside the accelerator wheel housing. The accelerator wheel receives the seeds from the accelerator wheel housing and accelerates the seeds from the V Seed Meter Release  to the V Accelerated Seed Release  value and releases the seeds from the accelerator wheel housing with the V Accelerated Seed Release-Horizontal  value substantially equal to the V Planter  value. 
         [0007]    According to another aspect of the invention, the seed disk of the seed meter has seed disk pockets holding the individual seeds relative to the seed disk while the seeds are conveyed by the seed disk through the seed meter housing. The accelerator wheel of the accelerator wheel system further includes accelerator wheel pockets holding the individual seeds relative to the accelerator wheel while the seeds are conveyed by the accelerator wheel through the accelerator wheel housing. The accelerator wheel pockets may rotate with a relatively greater angular velocity in the accelerator wheel housing than the seed disk pockets in the seed meter housing and the accelerator wheel may have a relatively larger diameter than the seed disk. The accelerator wheel and the seed disk may be rotated by a common drive system. The drive system may drive one of the accelerator wheel and the seed disk, and accelerator wheel and seed disk may be in driving and driven connection with each other, for example, by way of an intermediate gear. 
         [0008]    According to another aspect of the invention, the accelerator wheel pockets extend into an outer circumferential surface of the accelerator wheel. The outer circumferential surface of the accelerator wheel may include ramped segments extending between the accelerator wheel pockets. Each ramped segment extends between a pair of accelerator wheel pockets with the respective pair of accelerator wheel pockets. The pair of accelerator wheel pockets includes a leading accelerator wheel pocket and a trailing accelerator wheel pocket, with the leading accelerator wheel pocket arranged relatively ahead of the trailing accelerator wheel pocket with respect to a direction of rotation of the accelerator wheel. 
         [0009]    According to another aspect of the invention, each ramped segment between the pockets of the accelerator wheel may include a leading end proximate the respective leading accelerator wheel pocket and a trailing end proximate the respective trailing accelerator wheel pocket. The leading end of the ramped segment is spaced relatively farther from an axis of rotation of the accelerator wheel than the trailing end of the ramped segment. Each ramped segment may extend at least partially angularly from the leading end to the trailing end, along a tightening radius relative to the axis of rotation of the accelerator wheel. This provides a generally saw-tooth-type perimeter shape to the accelerator wheel. At each pair of adjacent ramped segments, a transition is defined between a first ramped segment and a second ramped segment. A first radius is defined between the trailing end of the first ramped segment and the axis of rotation of the accelerator wheel. A second radius is defined between the leading end of the second ramped segment and the axis of rotation of the accelerator wheel. A step change in radius value may be defined between the first radius of the trailing end of the first ramped segment and the second radius of the leading end of the second ramped segment. Each accelerator wheel pocket may at least partially define the transition between the respective first and second ramped segments arranged opposite the respective accelerator wheel pocket(s). In this way, each accelerator wheel pocket may define the trailing accelerator wheel pocket relative to the first ramped segment and the leading accelerator wheel pocket relative to the second ramped segment. 
         [0010]    According to another aspect of the invention, the accelerator wheel housing includes an accelerator wheel housing outlet and a seed tube that extends away from the accelerator wheel housing outlet. The seed tube directing the seeds released from the accelerator wheel housing to the field. This provides the accelerator wheel system between the seed tube and the seed meter, allowing accelerator wheel system to provide correction anomalous seed spacing and timing characteristics and to increase the seed velocity so that the seeds leave the seed tube at a velocity of approximately zero mph relative to the field. 
         [0011]    Other aspects, objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
           [0013]      FIG. 1  illustrates a simplified schematic view of a planter with seed meters with accelerator wheel systems in accordance with the present invention; 
           [0014]      FIG. 2  illustrates a variant of the planter of  FIG. 1 ; 
           [0015]      FIG. 3  illustrates a cross-sectional top plan view of a seed meter and accelerator wheel system of the planter of  FIG. 1 ; 
           [0016]      FIG. 4A  illustrates a cross-sectional rear elevation view of a seed meter and accelerator wheel system of the planter of  FIG. 1 ; 
           [0017]      FIG. 4B  illustrates a cross-sectional rear elevation view of a variant of the seed meter and accelerator wheel system  FIG. 4A ; 
           [0018]      FIG. 4C  illustrates a cross-sectional rear elevation view of another variant of the seed meter and accelerator wheel system  FIG. 4A ; 
           [0019]      FIG. 5  illustrates a cross-sectional side elevation view of a seed meter and accelerator wheel system of the planter of  FIG. 1 ; and 
           [0020]      FIG. 6  illustrates a close-up cross-sectional side elevation view of a portion of a seed meter and accelerator wheel system of the planter of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring now to the drawings and specifically to the simplified schematic representations of  FIGS. 1 and 2 , planter  5  is shown with row units  7 , each having a seed meter  9  and an accelerator wheel system  11  that minimizes seed tumble of the seeds being planted by delivering the seeds to an agricultural field at a rearward velocity that matches a forward velocity of the planter  5 , as explained in greater detail elsewhere herein. Planter  5  may be or may include components of planters available from Case III, such as the EARLY RISER® series planters. The planter  5  is towed behind a tractor  15  to move through the field in a planter travel direction with a planter velocity (V Planter ) and has a chassis  17  with a frame including a toolbar  19  that supports the multiple row units  7 , which are substantially identical. Each row unit  7  has ground-engaging tools (not shown) that may include opening and closing mechanisms such as opener disks and closing disks, respectively, or other ground-engaging tools for opening and closing a furrow. The ground-engaging tools may also include a gauge wheel configured for adjusting furrow depth by limiting soil penetration of the furrow-opening mechanism of the ground-engaging tools while creating a furrow and a press wheel to roll over the closed furrow to firm the soil over the seed to further close the furrow and promote favorable seed-to-soil contact. Seeds are stored in bulk on the planter  5  in a bulk seed storage system  21  that delivers the storage seed to the row units  7 . Referring now to  FIG. 1 , the seed storage system  21  is shown as a central bulk storage system with bulk fill tanks  23  that hold the seeds in bulk that will be pneumatically delivered from the bulk fill tanks  23  to the seed meters  9  at the row units  7 . Referring now to  FIG. 2 , the seed storage system  21  is shown as an on-row bulk storage system, with on-row bulk fill hoppers  25  that hold the seeds in bulk that will be gravity fed to the seed meters  9  at the row units  7 . 
         [0022]    Referring now to  FIGS. 3-4C , regardless of where the seeds are stored on the planter  5  and how the seeds are delivered to the seed meters  9  at the row units  7  ( FIGS. 1 and 2 ), each seed meter  9  includes an internal seed disk  27  with seed disk pockets  29  for picking up and carrying the individual seeds through the seed meter  9 . At each row unit  7  ( FIGS. 1 and 2 ), seed disk drive system  31  rotates the seed disk  27  of the seed meter  9  through a seed pool inside of the seed meter  9  to expose the seed disk pockets  29  to the seeds in the seed pool to pick up the seeds in the seed disk pockets  29 . Although shown as extending axially through or between opposing surfaces of the seed disk  27 , the seed disk pockets  29  may extend at least partially into an outer circumferential surface of the seed disk  27 . The seed meters  9  can be purely mechanical-type seed meters  9  or can be pneumatic seed meters  9 , as shown. Pneumatic seed meters  9  are operatively connected to an airflow system  33  ( FIGS. 3-4C ). The airflow system  33  may include a positive air pressure source and/or a vacuum source for establishing positive and/or vacuum pressures and corresponding air flows for operation of seed meters  9  at the row units  7 , such as within air pressure chambers of the seed meters  9 . The positive air pressure source and vacuum sources can be known pumps, fans, blowers, and/or other known airflow system components. When the seed storage system  21  is configured with a central bulk storage system ( FIG. 1 ), the airflow system  33  includes a seed conveyance airflow system providing an airflow that entrains the seeds to move the seeds from bulk storage in the bulk fill tanks  23  through seed conduits to the row units  7 , such as to mini-hoppers (not shown) that feed the seed meters  9 . When the seed meters  9  are positive pressure pneumatic seed meters  9 , the airflow system  33  is configured to provide a positive airflow and a corresponding positive pressure within the seed meters  9  to push seeds into and hold the seeds in the seed disk pockets  29  of the seed disks  27  by positive pressure through introducing pressurized air into the seed meters  9 . When the seed meters  9  are vacuum pressure pneumatic seed meters  9 , the airflow system  33  is configured to provide a vacuum airflow and a corresponding negative pressure within the seed meters  9  to pull and hold the seeds in the seed disk pockets  29  of the seed disks  27  by vacuum pressure introduced into the seed meters  9  by evacuating air out of the seed meters. 
         [0023]    Still referring now to  FIGS. 3-4C , each seed meter  9  has a seed meter housing  35  that includes interconnected covers, shown as a seed-side cover  37  and a vacuum-side cover  39  that collectively enclose the interior of the seed meter  9  and cover the seed disk  27 . The seed-side cover  37  is arranged parallel, to and spaced from the seed disk  27 . Referring now to  FIG. 3 , a seed reservoir  41  in which the seed pool collects is defined in the space between the seed-side cover  37  and the seed disk  27 . A seed inlet  43  extends through the seed-side cover  37  to define a passageway as an entry point allowing seeds to enter the seed reservoir  41  from the bulk seed storage system  21  or the on-row bulk storage system. with on-row bulk fill hoppers  25  ( FIGS. 1 and 2 ). Referring again to  FIGS. 3-4C , the vacuum-side cover  39  is arranged parallel to and spaced from the seed disk  27 , on the other side of the seed disk  27  than the seed-side cover  37 . An air pressure chamber shown as vacuum chamber  45 , in which the vacuum pressure is created in the seed meter housing  35 , is defined in the space between the vacuum-side cover  39  and the seed disk  27 . Vacuum inlet  47  extends through the vacuum-side cover  39  to define a passageway through which air can flow out of the seed meter housing  35  to establish vacuum pressure inside the seed meter  9 . Release location  49  is defined inside of seed meter housing  35  where the seeds are released from the seed disk pockets  29 , which may correspond to a position of vacuum cutoff in the seed meter housing  35 . Seed meter housing  35  includes seed meter housing outlet  51  that is configured to direct the seeds out of the seed meter housing  35  during seed meter exiting events at seed meter release velocity (V Seed Meter Release ), into the accelerator wheel system  11 . 
         [0024]    Still referring to  FIGS. 3-4C , the accelerator wheel system  11  mitigates seed tumble and improves seed spacing at relatively faster planter travel speeds, The accelerator wheel system  11  corrects timing and thus spacing anomalies of seeds being released from seed disk  27  of the seed meter  9  if there are incorrect seed disk release events and increases the velocity of the seeds to release the seeds from the accelerator wheel system  11  to approximate the planter travel speed V Planter  to provide a relative velocity of the released seeds with respect to the ground or field of approximately zero mph, substantially eliminating seed tumble during planting. The accelerator wheel system  11  includes accelerator wheel housing  53  with inlet  55  receiving the individual seeds released out of the seed meter housing outlet  51  and an accelerator housing outlet  57  that delivers the seeds into seed tube  59  for directing the seeds from the accelerator wheel system  11  and thus the row unit  7  ( FIGS. 1 and 2 ) to the seed trench. Accelerator wheel  61  is arranged for rotation inside the accelerator wheel housing  53 . An upper portion of the accelerator wheel  61  is transversely stacked with respect to or overlaps a lower portion of the seed disk  27  ( FIGS. 4A-4C and 5 ). The accelerator wheel  61  has accelerator wheel pockets  63  holding the individual seeds while moving the seeds through the accelerator wheel housing  53 , from inlet  55  to outlet  57  for release through an exit of the seed tube  59 . Accelerator wheel pockets  63  extend into an outer circumferential surface  65  that defines an outer periphery of the accelerator wheel  61 . 
         [0025]    Referring now to  FIGS. 5 and 6 , the outer circumferential surface  65  of accelerator wheel  61  has ramped segments  67  extending between respective pairs of accelerator wheel pockets  63 . Referring now to  FIG. 6  and shown at the lower portion of the accelerator wheel  61 , each accelerator wheel pocket  63  has a front pocket wall  63 A. a back pocket wall  63 B, and a lower pocket wall  63 C interconnecting the front and back pocket walls  63 A,  63 B. The front and back pocket walls  63 A,  63 B extend at non-perpendicular angles with respect to the outer circumferential surface  65 , extending angularly away from the direction of rotation of the accelerator wheel  61 . The lower pocket wall  63 C extends along an arc to connect respective ends of the front and back pocket walls  63 A,  63 B, Referring again to  FIG. 5 , each accelerator wheel pocket  63  defines a leading accelerator wheel pocket with respect to the adjacent accelerator wheel pocket  63  behind it and also defines a trailing accelerator wheel pocket  63  with respect to the accelerator wheel pocket  63  in front of it, relative to the direction of rotation of the accelerator wheel  61 . Between each adjacent pair of seed pockets  63 , each ramped segment  67  of the accelerator wheel  61  has a leading end  69  near the corresponding first or leading seed pocket  63  and a trailing end  71  near the corresponding second or trailing seed pocket  63 . As shown in  FIGS. 5 and 6 , each ramped segment  67  has its leading end  69  ( FIG. 5 ) connected to the outer end of the back pocket wall  63 B ( FIG. 6 ) of the respective leading seed pocket  63  and extends in a direction away from the direction of rotation of the accelerator wheel  61  to its trailing end  71  ( FIG. 5 ) connected to the outer end of the front pocket wall  63 A ( FIG. 6 ) of the respective trailing seed pocket  63  of the pair of seed pockets  63  at the opposite ends of the ramped segment  67 . The accelerator wheel  61  is shown with a generally saw-tooth-type perimeter shape, although it is understood that the accelerator wheel  61  may have other perimeter shapes. The saw-tooth-type perimeter shape is provided by a configuration of the accelerator wheel  61  with the ramped segment leading end  69  spaced relatively farther from an axis of rotation of the accelerator wheel  61  than the ramped segment trailing end  71 . Each ramped segment  67  extends at least partially angularly, which may also curve, from the leading end  69  to the trailing end  71 , along a tightening radius relative to the axis of rotation of the accelerator wheel  61 . Between a pair of adjacent ramped segments  67 , a transition  73  providing a step change in radius value of the accelerator wheel  61  is defined between the first radius of the ramped segment trailing end  71  of a first ramped segment  67  of the pair and the second radius of the ramped segment leading end  69  of the second ramped segment of the pair. The transition  73  can be defined at least partially by the accelerator wheel pocket  63  between each pair of ramped segments  67 . 
         [0026]    Referring again to  FIG. 6 , the ramped segments  67  cooperate with a guide  75  extending between the seed meter housing outlet  51  and the accelerator housing inlet  55 . The guide  75  has a pair of guide surfaces  77  that are inclined with respect to each other, tapering downwardly from the seed meter  9  to the accelerator wheel system  11  to facilitate funneling of the seeds falling from the release location  49  into the accelerator wheel system  11 . A space between upper ends of the guide surfaces  77  defines the seed meter housing outlet  51 . A space between lower ends of the guide surfaces  77  defined the accelerator housing inlet  55 . A spacing correction arrangement  83  is defined by guide  75 , accelerator wheel ramped segments  67 , accelerator wheel pocket  63 , and an inner surface  79  of a circumferential side wall  81  accelerator wheel housing  5 , that cooperate with each other to provide spacing correction of mis-released seeds from the seed meter  9  by facilitating receipt of the seeds in the pocket  63  as a re-spacing event(s) before planting. When seeds fall from the release location  49  with a seed meter  9  through the guide  75 , if a seed is not immediately received in the accelerator wheel pocket  63 , then the seed will momentarily be held within the spacing correction arrangement  83  until it is received in an advancing accelerator wheel pocket  63 . This is because the seed is temporarily impinged in a space  85  between the accelerator wheel outer circumferential surface  65  in the circumferential side wall inner surface  79  of the accelerator wheel housing  53  while the ramped segment  67  slides underneath the seed, gradually increasing the height dimension of the space  85  until an advancing accelerator wheel pocket  63  passes underneath and receives the seed to carry the seed through the rest of the accelerator wheel housing  53  until the seed reaches and passes through the outlet  57 . For relatively larger seeds that do not fit in the space  85 , if the seed is not immediately received in an accelerator wheel pocket  63 , the seed is held in the guide  75  while the ramped segment  67  slides underneath the seed, until an advancing accelerator wheel pocket  63  passes underneath and receives the seed to carry the seed through the rest of the accelerator wheel housing  53  until the seed reaches and passes through the outlet  57 . 
         [0027]    Referring now to  FIGS. 1, 2, and 4A-4C , during use, drive system  31  rotates the seed disk  27  ( FIGS. 4A-4C ) and accelerator wheel  61 . Drive system  31  includes a transmission assembly  89  selectively delivering power to the seed meters  9  and accelerator wheel system  11  for rotating the seed disk  27  ( FIGS. 4A-4C ), and accelerator wheel  61  is controlled by control system  91 . Control system  91  includes a tractor control system and/or planter control system, which can include an industrial computer or, e.g., a programmable logic controller (PLC), along with corresponding software and suitable memory for storing such software and hardware including interconnecting conductors for power and signal transmission for controlling electronic, electro-mechanical, and hydraulic components of the seed meters  9 , accelerator wheel system  11 , other components of the planter  5  and/or tractor  15 . Control system  91  monitors the travel speed of the tractor  15  and thus planter velocity V Planter  and controls rotational speed of the accelerator wheel system  11  to provide a desired seed delivery velocity from the accelerator wheel system  11  to match planter velocity V Planter  so that a relative velocity of the released seeds with respect to the ground or field is approximately zero mph, such as less than about 1 mph or 0.5 mph, or sufficiently slow to prevent seed tumble that would move the seed more than about 2 inches or more than about 1 inch within the furrow, as explained in greater detail elsewhere herein. 
         [0028]    Referring to  FIGS. 1 and 2 , the transmission assembly  89  is shown with mechanical chain drives  93  that deliver rotating driving power from a rotating shaft  95 . Shaft  95  is driven to rotate from the ground through movement of the planter  5 , such as by a traction-drive-type drive wheel, ground-engaging drive sprocket, or may be rotated by a motor such as an electric motor, pneumatic motor, or hydraulic motor. Clutches  97  are controlled by the control system  91  to engage and disengage for selectively transmitting rotation of the shaft  95  into movement of chains of the chain drives  93 . It is understood that instead of chains and sprockets, chain drives  93  may incorporate other power transmission components such as belts and pulleys. Referring now to  FIG. 4A , chain drive  93  ( FIGS. 1 and 2 ) rotates a sprocket  99  attached to a rotating accelerator wheel shaft  101  connected to hub  103  that supports and rotates the accelerator wheel  61 . Gear train  105  includes gears  107  that drivingly connect the accelerator wheel  61  to the seed disk  27 . The gears  107  transmit rotation of the accelerator wheel shaft  101  to a shaft  108  connected to hub  109  that supports and rotates seed disk  27 . Referring now to  FIG. 4B , unlike the accelerator wheel system  11  of  FIG. 4A  that initially drives the accelerator wheel  61 , the accelerator wheel system  11  is shown configured to initially drive the seed disk  27 . Chain drive  93  ( FIGS. 1 and 2 ) rotates sprocket  99  attached to seed disk shaft  108  that rotate the hub  109  rotates seed disk  27 . Gear train  105  transmits power from seed disk shaft  108  to accelerator wheel shaft  101  to rotate hub  103  and accelerator wheel  61 . It is understood that the chain drive(s)  93  may instead drive an intermediate or jack shaft (not shown) that delivers power for rotating both the seed disk  27  and the accelerator wheel  61  through separate chains receiving power from the jack shaft. Referring now to  FIG. 4C , it is understood that the transmission assembly  89  can be configured to separately drive rotation of seed disk  27  and accelerator wheel  61 , as controlled by control system  91 .  FIG. 4C  shows the drive system  31  having a motor  88 A such as an electric motor, pneumatic motor, or hydraulic motor, separately controlled by control system  91 , and separately driving each of, the seed disk  27  and accelerator wheel  61 . Motors  88 A are shown with output shafts coaxially connected to and directly driving the shafts  101 ,  108  and thus also driving hubs  103 ,  109  and accelerator wheel  61  and seed disk  27 , respectively. It is understood that motors  88 A may instead drive the hubs  103 ,  109  themselves or the accelerator wheel  61  and seed disk  27 , themselves, such as through cooperating toothed surfaces of sprockets or gear-type interfaces at outer circumferential surfaces, flanges, or other interfaces. Regardless of how motors  88 A drive rotation of the seed disk  27  and accelerator wheel  61 , sensors  88 B are arranged with respect to the seed meter and accelerator wheel housings  35 ,  53  to detect rotational speed(s) of seed disk  27  and accelerator wheel  61 . Control system  91  receives signals from the sensors  88 B corresponding to the respective rotational speed(s) of seed disk  27  and accelerator wheel  61  and controls to the motors  88 A to synch or keep timed the rotations to achieve desired delivery rate and velocity according to programming of the control system  91 . 
         [0029]    Referring again to  FIGS. 4A-4C , during use, drive system  31  rotates the seed disk  27  and the accelerator wheel  61  so that the accelerator wheel pocket  63  has a greater angular velocity than the seed disk pockets  29 . This can be done by arranging the accelerator wheel pocket  63  radially farther from an axis of rotation of the accelerator wheel  61  than a radial distance from the seed disk pockets  29  from the axis of rotation of the seed disk  27  and also rotating the accelerator wheel  61  at faster rotational speed and the seed disk  27 . In this way, seeds leave the accelerator wheel system  11  at a greater velocity than that at which the seeds left the seed meter  9 . The accelerator wheel system  11  can accelerate the seeds to a relatively greater velocity in the accelerator wheel system  11 , which can be at least about five times, at least about eight times, or at least about ten times greater than the velocity of the seeds in the seed meter  9 . The rotational speed differential between the rotational speeds of the seed disk  27  and accelerator wheel  61  can be provided by the gear train  105  by separately driving the seed disk  27  and accelerator wheel  61  at different rotational speeds ( FIGS. 4A and 4B ) or by directly separately driving seed disk  27  and accelerator wheel  61  at different speeds by way of motors  88 A ( FIG. 4C ). 
         [0030]    Referring again to  FIG. 6 , regardless of how the rotational speed differential between the rotational speeds of the seed disk  27  and accelerator wheel is established, seeds are accelerated in the accelerator wheel system  11  compared to seed velocity in the seed meter  9 . As represented by the vertical solid line arrow pointing down and labeled  111 , each seed is released from the seed disk  27  through the seed meter housing outlet  51  at a seed meter release velocity (V Seed Meter Release ) the value that relates to the angular velocity of the seed disk pockets  29  ( FIG. 4 ) and acceleration due to gravity. The seed is directed through the guide  75  into accelerator wheel system  11 . Accelerator wheel system  11  accelerates seed to a relatively greater velocity and releases the seed out of the accelerator wheel housing outlet  57  and the seed tube  59 , traveling at an accelerated seed release velocity (V Accelerated Seed Release ) toward the seed trench. The V Accelerated Seed Release  value is represented by the angled solid line arrow pointing away from the seed tube  59  and labeled  113 . The V Accelerated Seed Release  value  113  has a vertically oriented velocity component and a horizontally oriented velocity component. The horizontally oriented velocity component of the V Accelerated Seed Release  value  113  is shown as horizontal velocity component (V Accelerated Seed Release-Horizontal ) value as represented by the dashed line arrow pointing to the right and labeled  115 . The V Accelerated Seed Release-Horizontal  value  115  is in the opposite direction and substantially equal to the V Planter  value of the planter velocity as represented by the dashed line arrow pointing to the left and labeled  117 . This provides a relative velocity of the released seeds with respect to the ground of approximately zero mph, substantially eliminating seed tumble during planting. 
         [0031]    Still referring to  FIG. 6 , to maintain a relative velocity of the released seeds with respect to the ground of approximately zero mph, the control system  91  evaluates data corresponding to signals from a pair of seed sensors  119  that are spaced from each other and arranged upon the seed tube  59  and configured to detect seed traveling past each sensor  119 . Control system  91  calculates the V Accelerated Seed Release  value  113  and/or the V Accelerated Seed Release-Horizontal  value  115  by dividing the fixed distance between the seed sensors  119  by the time that it takes the seed to travel from the first upstream sensor  119  to the second downstream sensor  119 . Control system  91  evaluates the V Accelerated Seed Release-Horizontal  value  115  to the V Planter  value  117  and can be determined by the control system  91  based on a signal from speed sensor  121  arranged at the tractor  15  ( FIGS. 1 and 2 ). If control system  91  identifies a discrepancy between the V Accelerated Seed Release-Horizontal  value  115  and the V Planter  value  117 , the control system  91  commands the drive system  31  to rotate the accelerator wheel  61  at a faster or slower rotational speed to attenuate the discrepancy between the V Accelerated Seed Release-Horizontal  value  115  and the V Planter  value  117 . 
         [0032]    Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.