Abstract:
An apparatus and method for controlled delivery of seeds between the seed meter of an agricultural planter to an open seed furrow. Seeds are received individually and in a sequence from a seed meter into a housing. The seeds are conveyed in sequence through the housing by a conveyor at a controlled speed to a location proximate the open furrow, then gently released into the open furrow as the agricultural planter moves forward. The controlled delivery of the seed to the furrow ensures more accurate seed placement within the furrow at the desired seed spacing, thereby improving crop yield potential.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention: 
     The present invention relates generally to agricultural seed planters, and more particularly to devices for delivering seed from the planter&#39;s seed meters to the open seed furrows. 
     2. Description of Related Art: 
     It is well recognized that uniformity in the spacing of seeds in a seed furrow is essential for maximizing a field&#39;s crop yield and thus enhancing the profitability of the farmer&#39;s operation. Modern agricultural planters use various types of seed metering devices designed to select and discharge individual seeds at regular intervals, to ideally achieve this uniformity in seed spacing. 
     The various types of seed metering devices currently being used on agricultural seed planters can generally be divided into two categories on the basis of the seed selection mechanism employed, namely, mechanical or pneumatic. The commercially available mechanical meters include finger-pickup meters such as disclosed in U.S. Pat. No. 3,552,601, cavity-disk meters such as disclosed in U.S. Pat. No. 4,613,056, and belt meters such as disclosed in U.S. Pat. No. 5,992,338. Commercially available pneumatic meters include vacuum-type meters such as disclosed in U.S. Pat. No. 5,501,366, and compressed air meters. Other commercially available meters combine the seed selection mechanisms of both mechanical and pneumatic meters such as disclosed in U.S. Pat. No. 4,074,830. 
     Regardless of whether they are of the finger-pickup type, vacuum-disk type, cavity-disk type or belt-type, the seed meters typically are mounted just below the seed hopper at heights ranging from about eighteen to about twenty-four inches above the ground surface. As a result, planters employing such metering devices also require seed tubes to direct the seeds into the open seed furrow after the singulated seeds are discharged from the seed meter. 
     It has been found that the use of seed tubes to deliver the seeds to the seed furrow have a negative effect on the uniformity of seed spacing in the furrow. This is due to the fact that some of the seeds descend through the seed tube rapidly, substantially in a free-fall through the entire length of the seed tube, while other seeds contact the walls of the seed tube more frequently as they descend through the seed tube, even to the point of ricocheting between opposite sides of the seed tube. These differences in the degree of contact with the seed tube lead to differences in the rates at which the seeds travel through the tube. In fact, it has been shown that on occasion a later-discharged seed from the seed meter will actually pass an earlier-discharged seed as both descend through the seed tube. 
     Several factors contribute to this problem. As an agricultural planter traverses a field, surface irregularities in the field lead to momentary jostling, vibration or other positional shifting of the planter components, including the seed tubes. Irregularities among the seeds themselves may be a factor as well. In any event, the uniformity at which seeds enter the seed tube after exiting the seed meter is typically not present as the seeds exit the seed tube. Further, although each seed tube performs the useful function of guiding its seeds toward the open furrow, the differences in velocities at which the seeds exit the seed tube toward the ground have an adverse effect on uniformity of seed spacing in the furrow. 
     Thus, there is a need in the agricultural industry for an apparatus and method for controlled delivery of the seed between the seed meter and the open furrow that improves seed placement accuracy within the open furrow at the desired seed spacing thereby improving crop yield and the efficiency and profitability of farming operations. 
     BRIEF SUMMARY OF THE INVENTION 
     A seed dispensing apparatus and method for controlled delivery of seeds from an agricultural planter&#39;s seed meter to an open furrow. The apparatus includes a conveyor support structure adapted for receiving individual seeds discharged by a seed metering device of an agricultural planter. The conveyor support structure includes a first end positioned near the seed metering device to receive seeds metered individually and in a sequence therefrom. A second end of the conveyor support structure is positioned proximate an open furrow in an agricultural field for movement along the furrow as the agricultural planter traverses the field. The apparatus further includes a seed conveyor mounted movably relative to the conveyor support structure. The seed conveyor is operable at a controlled conveyor speed to transport the seeds, in the sequence in which they are received from the seed meter, at the controlled conveyor speed from the first end toward the second end of the conveyor support structure. The conveyor further is operable to serially release the seeds proximate the second end of the conveyor support structure to dispense the seeds in sequence into the open furrow. 
     The conveyor support structure advantageously is provided as a housing, with an opening at the first end to receive the seeds from the seed meter, and an opening at the second end to dispense the seeds into the furrow. The housing, confines the seeds to more positively ensure their travel with the conveyor, and substantially at the controlled conveyor speed until they are dispensed. 
     In one preferred form, the seed conveyor includes an endless belt and a plurality of evenly spaced-apart flights extended outwardly from the belt. Each pair of adjacent flights cooperates with the belt to provide a seed compartment. At the first end, seeds are sequentially loaded into the compartments, one seed into each compartment. As the compartments travel from the first end to the second end for dispensing, walls of the housing cooperate with the belt and flights to retain each seed within its associated compartment until the compartment emerges from the housing at the second end, whereupon the seed is dispensed to the furrow. 
     Preferably the second end of the seed dispensing device is located near a top of the open furrow. If desired, the dispensing device incorporates a seed guide extending from the second end toward a bottom of the furrow, to further guide each seed as it descends toward the bottom of the furrow. 
     In an alternative approach, the seed conveyor includes two endless belts, juxtaposed to provide a conveyance path along which respective segments of the belts face one another in substantially uniform spaced-apart relation. The conveyance path extends from the first end to the second end, and along the conveyance path the opposing belt segments are driven in the same direction and at the same controlled conveyor speed. The distance between the opposed belt segments is less than the size (diameter or equivalent approximation) of the seeds. Consequently the seeds are maintained between the opposed belt segments by belt elasticity and friction as they are carried from the first end to the second end for dispensing. 
     The seed conveyor, whether a single flighted belt or a pair of confronting belts as just described, can be driven by a pulley operably coupled to the seed meter, with result that the controlled conveyor speed is governed by the seed meter speed. This arrangement advantageously assures that a uniform dispensing of seeds from the seed meter results in a uniform spacing of seeds along the seed conveyor. This arrangement also more positively ensures a one-to-one relationship of seeds and compartments, when the seed conveyor is provided as a single, flighted belt. 
     In an alternative arrangement, the drive pullies of the seed conveyor can be driven independently of the seed meter, such as by being operably coupled to an independently driven drive shaft or the lee. In this way, the spacing of the seeds could be momentarily increased or decreased depending on ground speed independent of the dispensing speed of the seed meter. 
     According to an alternative form of the invention, a seed meter and seed delivery apparatus are provided in combination. The seed delivery apparatus is adapted to receive individual seeds discharged from the seed meter, and to controllably convey the individually dispensed seeds to an open furrow. The seed delivery apparatus comprises a housing in comnmunication with the seed meter to receive the individually discharged seeds. The housing is adapted to be operably supported by a row unit frame of an agricultural planter, and has an open end terminating near the soil surface in substantial alignment with the open furrow. A seed conveying assembly is disposed in the housing, and adapted to individually convey the individually discharged seeds through the housing at a substantially constant predetermined velocity toward the open end of the housing for a depositing of the seeds into the open furrow. 
     Further in accordance with the present invention, there is provided an improved agricultural seed planter having a main frame operably supporting a plurality of adjacently spaced row units, each of the row units having a row unit frame supporting a seed hopper, a seed meter adapted to discharge individual seeds at regular intervals, and a seed delivery device adapted to receive the individual seeds discharged from the seed meter and to convey the individually discharged seeds at a controlled conveyor speed to a location near an open furrow for dispensing the seeds into the furrow. 
     Thus in accordance with the present invention, the seeds associated with a given row unit are received individually and in a sequence from their associated seed meter, conveyed at a controlled conveyor speed to a location proximate an open furrow, then released into the furrow in the same sequence, as the agricultural planter moves forward. This ensures a more even spacing between adjacent seeds, improving the crop yield and enhancing the efficiency of the farming operation. 
    
    
     To the accomplishment of the above objectives, features and advantages, this invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific form illustrated and described within the scope of the appended claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a conventional agricultural planter showing the prior art seed tube for delivering the seeds discharged from a seed meter to the seed furrow. 
     FIG. 2 is a side elevation view of the conventional agricultural planter of FIG. 1 with the prior art seed tube replaced by an embodiment of the seed delivery apparatus of the present invention shown receiving seeds from a seed meter. 
     FIG. 3 is an exploded perspective view of the seed delivery apparatus of FIG.  2 . 
     FIG. 4 is a side elevation view of the conventional agricultural planter of FIG. 1 with the prior art seed tube replaced by another embodiment of the seed delivery apparatus of the present invention shown receiving seeds, for example, from a conventional finger-pickup type seed meter. 
     FIG. 5 is a side elevation view of the conventional agricultural planter of FIG. 1 with the prior art seed tube replaced by another embodiment of the seed delivery apparatus of the present invention shown receiving seeds, for example, from a conventional vacuum-type seed meter. 
     FIG. 6 is a side elevation view of the conventional agricultural planter of FIG. 1 with the prior art seed tube replaced by another embodiment of the seed delivery apparatus of the present invention shown receiving seeds, for example, from a conventional belt-type seed meter. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Drawing FIG. 1 shows part of a typical agricultural planter  10 , such as that disclosed in U.S. Pat. No. 4,009,668, which is incorporated herein by reference. As is conventional, the planter  10  includes a mobile main frame  12 , only a portion of which is illustrated in FIG.  1 . The main frame  12  is conventionally attached to and towed by a tractor (not shown) and a number of individual row units  14  are spaced at intervals along the main frame  12 . Each row unit  14  includes a row unit frame  16 , vertically adjustable relative to the main frame  12  by a parallel linkage  18 . While only one row unit  14  is shown and described herein, the other row units on planter  10  are substantially the same. As is conventional, each row unit  14  includes a seed hopper  20  and a fertilizer hopper  22  mounted on the row unit frame  16 . Each row unit  14  has a seed selection and dispensing device  24 , commonly referred to as a seed meter, which receives seed from the seed hopper  20  and discharges the seeds  25  into a seed tube  26  at regular intervals. As shown in FIG. 1, and as explained in greater detail later, some planters, such as the John Deere 7000 and 7100 series planters with finger-pickup type seed meters, utilize a flighted seed belt assembly  60  disposed adjacent the seed meter to receive the seeds discharged by the seed meter  24 . This flighted seed belt assembly  60  then conveys the seeds downwardly a short distance before dispensing the seeds into the seed tube  26 . 
     A furrow opening assembly  30 , disposed at the lead end of the row unit  14 , typically comprises a pair of furrow opening disks  32  that rotate on shafts  34 . The shafts  34  are supported by downwardly extending brackets from a row unit subframe  38 . The axes of the respective furrow opening disks  32  are slightly inclined relative to one another so that the opening disks  32  contact one another forwardly and below the disk axes, preferably at ground level. In operation, the lower portions of the furrow opening disks  32  are disposed below the surface of the soil so that the disks from a V-shaped furrow  40  as the planter  10  traverses the field. The seed tube  26  deposits the seed in furrow  40  behind the axes of furrow opening disks  32 . A gauge wheel assembly  42  is mounted on the row unit subframe frame  38  adjacent the furrow opening disks  32 . The gauge wheel assembly  42  comprises a pair of gauge wheels  44  disposed adjacent the outer sides of the furrow opening disks  32 . A gauge wheel arm  46  connects each gauge wheel  44  to the row unit subframe  38 . An adjustable stop (not shown) operates between the row unit subframe  38  and the gauge wheel arm  46  to limit the upward movement of the gauge wheel  44  relative to the row unit subframe  38 . Since the gauge wheels  44  ride on the ground surface when the planter  10  is moving, the vertical position of the gauge wheels  44  relative to the furrow opening disks  32  controls the depth of the furrow  40 . A furrow closing assembly  48 , typically comprising a pair of rotatable canted wheels  50  supported from an arm  52  is disposed rearwardly of the furrow opening assembly  30  and the seed tube  26 , for closing the furrow  40  by pushing the soil back into the furrow over the deposited seeds. For greater detail, reference is made to said U.S. Pat. No. 4,009,668. 
     In regard to the furrow opening assembly  30 , it should be appreciated that some conventional planters utilize a furrow opening assembly having only one furrow opening disk, while still other furrow opening assemblies utilize a shovel or the like. Thus, reference to the furrow opening assembly throughout this specification is intended to include any structure employed to create a furrow in the soil. Similarly, reference to the furrow closing assembly throughout this specification is intended to include any apparatus employed for replacing the soil over the deposited seeds in the furrow. 
     As identified above, some commercially available planters, such as the John Deere 7000 and 7100 series planters with finger-pickup type seed meters, utilize a flighted seed belt assembly. As shown in FIG. 1, the flighted seed belt assembly  60  is typically attached adjacent the finger-pickup meter  24  to receive individual seeds discharged therefrom and to dispense the individual seeds into the seed tube  26 . For a more thorough discussion of the operation of a finger-pickup meter and its cooperation with the flighted seed belt assembly, reference may be made to U.S. Pat. No. 6,269,758 (Sauder) and to the parts catalog for the John Deere 7000 and 7100 MaxEmerge® Planting Units and Attachments, both of which are incorporated herein by reference. The seed belt asssembly  60  includes a substantially enclosed housing  62  comprised of side panels  64  spaced apart by a perimeter wall. In FIG. 1, one of the side panels  64  has been removed to show the internal components of the flighted seed belt assembly  60 . A seed receiving opening  68  in the side panel  64  of the housing  62  is disposed adjacent the seed discharge opening of the seed meter  24  to receive seeds therefrom. A flighted belt  70  having a plurality of spaced apart, outwardly extending flights is trained around a studded drive pulley  72  and an idler pulley  74 . The drive pulley  72  is rotatably driven by the drive shaft  76  of the finger-pickup meter  24 . The adjacent pairs of flights of the belt  70  form compartments, each compartment designed to carry a single seed from the seed receiving opening  68  downwardly to the open lower end of the housing  62  as shown where the seed is released into the seed tube  26 . 
     Referring now to drawing FIG. 2, the typical agricultural planter  10  of FIG. 1, is shown with the prior art seed tube  26  and seed belt housing  60  replaced by one embodiment of the seed delivery apparatus  100  of the present invention. As is apparent, the embodiment of the seed delivery apparatus  100  shown in FIGS. 2 and 3 is similar to the commercially available flighted seed belt housing  60  shown in FIG. 1, except that the flighted seed belt assembly has been elongated and modified for delivering seeds, individually in sequence and at a controlled conveyor speed, from the seed meter  24  all the way to the open furrow  40 . Thus, the above identified problems and disadvantages associated with dispensing individual seeds into a seed tube are eliminated. 
     As viewed in FIG. 2, The seed delivery apparatus  100  is preferably operably supported by the planter&#39;s row unit frame  16 . Generally, the seed delivery apparatus  100  comprises a conveyor support structure and a seed conveyor mounted movably relative to the conveyor support structure. In operation, the seed from the seed meter  24  enters the conveyor support structure at an upper end  102  through a seed receiving opening  104 . The seed conveyor then conveys the seeds  25  downwardly toward a lower end  106 , opened to allow dispensing of the seeds  25  into the furrow  40 . 
     With reference to FIG. 3, it is seen that the preferred conveyor support structure includes a housing  108  that substantially encloses the seed conveyor. The housing  108  includes a substantially flat panel  110 , and opposite panel  112  and a housing perimeter wall  114  perpendicular to the panels  110 ,  112 . The housing perimeter wall  114  and the panel  112  preferably form a unitary member of the housing  108  as shown. The housing  108  incorporates a lower, elongate region along which opposite segments  116  and  118  of housing wall  114  are parallel to one another. Elongate belt guides  120  and  122  are disposed inside the housing  108  along the lower region, and run parallel to the opposed housing wall segments  116 ,  118 . A seed guide  124  preferably extends downwardly from housing wall segment  116 . 
     A flange  126  extends outwardly from the upper region of housing wall  114 . Openings  128  through flange  126 , and corresponding openings  130  through an outer circumferential portion  131  of panel  110 , accommodate nut-and-bolt fasteners used to removably secure the panels  110 ,  112  and housing wall  114  together and thus form the substantially enclosed housing  108 . The upper portion of the housing  108  is preferably enlarged to facilitate a coupling of the seed delivery apparatus  100  to the seed meter  24 . The coupling is preferably releasable, such as by a bolted connection, enabling a retrofitting of the row unit  14  by attaching the seed delivery apparatus  100  in lieu of the prior art seed delivery structure incorporating the flighted seed belt assembly  60  and seed tube  26  described in connection with FIG.  1 . 
     In the embodiment of FIGS. 2 and 3, the seed conveyor comprises an endless belt  132 . A series of uniformly spaced apart apertures  134  are formed through the belt  132 . A series of flights  136  extend outwardly from the belt  132 , spaced apart from one another, by substantially the same distance. The seed delivery apparatus  100  further includes a plurality of pulleys to move and shape the endless belt  132 , including a drive pulley  138 . A plurality of studs  140  are preferably arranged circumferentially about the drive pulley  138 , uniformly spaced apart from one another the same distance as apertures  134  of the endless belt  132 . An opening  142  is provided through panel  112 , for receiving a drive mechanism, such as a drive shaft  144 , which also preferably drives the seed meter  24 . In most conventional planters, the seed meter  24  is driven by a shaft that is coupled to a sprocket and chain assembly that may be either ground driven or driven independently of the ground speed of the planter. Thus, the drive shaft  144  for rotating the drive pulley  138  may simply be an extension of the same shaft used to drive the seed meter  24 . The drive pulley  138  is operably removably coupled to the drive shaft  144  by any well known means, such as a key and pin arrangement, thereby providing rotational speed of the drive pulley  138  matched to the rotational speed of the seed meter  24 . 
     At the lower end  106  of the seed delivery apparatus  100 , the endless belt  132  is trained about an idler pulley  146 , rotatable about a sleeve  148  and secured between panels  110  and  112  by removable fasteners extending through elongated apertures  150  and  152  through panels  110  and  112 , to permit tension adjustment of the belt  132 . A tabbed idler pulley  154  is mounted rotatable on a sleeve  156  between the panels  110 ,  112 . The tabbed idler pulley  154  biases the endless belt  132  inwardly, providing a more secure wrapping engagement of the belt  132  around the drive pulley  138 . The tabbed idler pulley  154  has a plurality of outwardly extending tabs  158 , spaced apart from one another to positively interact with flighted belt  132 . 
     The idler pulleys  146  and  154  cooperate to maintain the endless flighted belt  132  wrapped about drive pulley  138  in a driving engagement with the studs  140  of the pulley extending into the apertures  134  of the belt  132 . As shown in FIG. 2, with the panel  112  removed, it is readily apparent that adjacent pairs of flights  136  cooperate with the endless belt  132  to form compartments, each compartment designed to carry a single seed from the seed receiving opening  104 , downwardly to the open lower end  106  of the housing  108 , where travel of each flight away from housing wall  114  releases the seed at a point near the top of the furrow  40 . As the belt  132  continues to move, the forward flight  136  of each compartment supports its associated seed, so that the seeds descend at the controlled conveyor speed. The belt guides  120  and  122  act upon the belt near the housing wall segments  116  and  118  to stabilize the belt along these segments. These guides  120 ,  122  further prevent oscillations in the endless belt that might carry the belt inwardly away from the housing wall  114 , thus tending to maintain the compartments substantially closed. In this manner, the belt guide  120  prevents each seed from slipping downwardly into the next adjacent compartment on its way to the point of release. 
     As perhaps best seen from FIG. 3, the flights  136  and the belt  132  have a width substantially equal to but less than the width of the housing wall  114 . Accordingly, although the flighted belt  132  moves freely within the housing  108 , the space between each panel  110 ,  112  and the flighted belt  132  is sufficiently narrow to prevent the escape of any seed from its compartment, until the intended point of release where movement of the belt  132  around the idler pulley  146  draws each flight  136  away from the housing wall  114 . Each seed, during its descent beyond the point of release, preferably encounters the seed guide  124  and is thereby gently directed to the bottom of the furrow  40 . 
     As previously noted, the same mechanism that operably drives the seed meter  24  also preferably rotates the drive pulley  138 . Accordingly, the endless belt  132  is driven at a conveyor speed synchronized to the seed meter speed, to ensure that as the seed meter  24  discharges seeds individually and in a sequence, the seeds are received sequentially into each of the moving compartments. 
     It should be understood that although reference has been made herein to the type of planter disclosed in U.S. Pat. No. 4,009,668, and to a finger-pickup type seed meter, the flighted belt type embodiment of the seed delivery apparatus  100  of the present invention may be used with any type of planter having any type of mechanical or pneumatic seed metering device disposed a distance above the soil surface. The embodiment disclosed herein is readily adapted to any type of planter or seed meter with only minor modifications which would be readily appreciated by those skilled in the art. For example, the length of the housing  108  and belt  132 , the positional relationship of the pulleys  138 ,  146 , and the location of the opening  104  will depend on the type of planter and the type of seed meter. For example, FIG. 2 shows the opening  104  disposed in the side panel  112  of the seed delivery apparatus  100  such as, for example, if the housing  108  was disposed adjacent the backing plate of a finger-pickup type meter. However, if the meter  24  was a vacuum-disk type meter or a belt-type meter, for example, the opening  104  may need to be located such that the seeds from the meter drop into the upper end  102  of the housing  108  through the perimeter wall  114 . Such minor modifications to the housing  108  with respect to the mounting of the housing to the planter frame  16  and positional relationship of the opening  104 , which are dependent upon the type of planter and seed meter utilized, would be readily appreciated by those skilled in the art, and therefore further discussion of such minor modifications to the embodiment disclosed herein is not warranted. 
     Drawing FIGS. 4-6 illustrate other alternative embodiments of the seed delivery apparatus  100  for receiving seeds from a seed meter  24  and delivering the seeds in a controlled manner to the seed furrow. Rather than utilizing a conveyor comprising a single flighted belt as shown if FIGS. 2 and 3, the embodiments shown in FIGS. 4-6 utilize a conveyor comprising two adjacently disposed belts  200 ,  202 . 
     The embodiment of the seed delivery apparatus  100  of FIG. 4 is shown operably supported with respect to the row unit frame  16  adjacent a finger-type seed meter  24 , for example, as described in U.S. Pat. No. 3,552,601 (Hansen) which is incorporated herein by reference. As with the previously described embodiment, the seed delivery apparatus  100  includes a housing  108  including a housing wall  114  and opposed panels  110 ,  112 . In FIG. 4, panel  110  has been removed for clarity. The conveyor includes a first endless belt  200  trained about a drive pulley  204 , an idler pulley  206  near the top of the seed delivery apparatus  100 , and an idler pulley  208  near the bottom of the apparatus  100 . An adjustable tensioning pulley  210  biases the belt  200  inwardly. A second endless belt  200  is trained about a drive pulley  212  and an idler pulley  214 , which can be mounted adjustably in a slot (not shown) for belt tensioning if desired. 
     Endless belts  200  and  202  are juxtaposed to provide confronting linear belt segments  216  and  218 , both of which travel downwardly is indicated by the arrows. Preferably, the drive pulleys  204  and  212  are synchronized such that belts  200  and  202  travel at the same controlled conveyor speed. Then, as each seed is discharged by the seed meter  24 , the discharged seed is captured between the endless belts  200 ,  202  at a conveyor entry point between pulleys  206  and  212  and conveyed downwardly toward the lower idler pulleys  208  and  214 . Confronting belt segments  216  and  218  are spaced apart from one another by a transverse distance less than the size (diameter or other suitable measurement) of the seeds, and are sufficiently flexible to undergo a slight elastic deformation due to each of the seeds positioned between the belts. Due to the localized deformation, the belts exert an elastic restoring force that acts, along with friction, to fix the seeds relative to the belts during downward travel toward pulleys  208  and  214 . The amount of the elastic restoring force for a given local displacement due to each seed can be adjusted by adjusting the belt tension, such as providing elongated mounting holes (not shown) in the face panels  110 ,  112 . In addition, the amount of elastic deformation required can be varied by adjusting the transverse displacement between segments  216  and  218  of the belts  200 ,  202 . This later adjustment also enables this conveyor to accommodate a variety of different sizes of seeds while providing substantially the same amount of elastic deformation between the belts for varying seed sizes. 
     In any event, belts segments  200  and  202  cooperate to provide a conveyance path, along which the seeds are moved, individually, in sequence, and at the controlled conveyor speed. As each seed is carried past pulleys  208  and  214 , the opposing segments  216 ,  218  of the belts  202  and  204  diverge about the pulleys, releasing the seed to a gradually inclined guide section  220  of the housing  108 , from which the seed is dispensed into the furrow  40 . 
     Drawing FIG. 5 schematically illustrates a further alternative embodiment of the seed delivery apparatus  100  adapted to receive seeds from a vacuum-type seed meter  24 , for example, as described in U.S. Pat. No. 5,501,366 (Fiorio) which is incorporated herein by reference. 
     Drawing FIG. 6 schematically illustrates a further alternative embodiment of the seed delivery apparatus  100  adapted to receive seeds from a belt-type seed meter  24 , for example, as described in U.S. Pat. No. 5,992,338 (Romans) which is also incorporated herein by reference. As is readily apparent between drawing FIGS. 4-6, the seed delivery apparatus  100  of the present invention is substantially the same, but, depending on the type of seed meter to which the seed delivery apparatus  100  is adapted, the profile of the housing  108  as well as the size and location of the drive pulleys  204 ,  212 , idler pulleys  206 ,  208  and  214 , and tensioning pulley  210  may need slight modification. Those skilled in the art would readily appreciate how to incorporate these minor variations between the embodiments of the seed delivery apparatus  100  for use with the various types of seed meters  24 , and therefore further discussion of these various embodiments is not warranted. 
     As shown, in FIGS. 2-6, the conveyor of the seed delivery apparatus  100  is driveably coupled to the seed meter  24 , and therefore synchronized with the seed meter  24 . As an alternative, any of the conveyors of the different embodiments of the present invention can be operably coupled to an independent drive mechanism such that the speed of the conveyor is independent the speed of rotation of the seed meter  24 . An independent drive mechanism is particularly adapted to the two-belt conveyor embodiments of FIGS. 4-6 since the belts do not include flights that are preferably timed with the seed dispensing rate of the seed meter as in the embodiment of FIGS. 2 and 3. 
     By driving the conveyor independently of the seed meter  24  the spacing of the seeds in the furrow could be controlled independent of the discharge rate of the seed meter. For example, the drive pulley(s)  204  and/or  212  could be operably coupled to the planter&#39;s ground wheels or possibly to an independently driven motor. If the drive pulley(s)  204  and/or  212  were coupled to the ground wheels of the planter, such as by a well known sprocket and chain assembly, the spacing of the seeds could be increased or decreased while on-the-go simply by increasing or decreasing the ground speed of the planter. For example, with reference to FIGS. 4-6, the distance shown between adjacent seeds along the conveyance path is uniform, determined by the rate of discharge from the seed meter and the speed of endless belts  200 ,  202 . By coupling the drive pulleys  204 ,  212  to the ground speed of the planter, instead of to the seed meter, the seed meter dispensing rate may remain constant while the conveyor speed may be reduced considerably, such as by one-half, for example. Thus, the spacing between adjacent seeds likewise would be reduced by one-half because the seed handling rate of the meter, in terms of number of seeds per unit time discharged by the meter would remain the same while the belt speed is reduced by one-half. The adjacent seeds would remain at one half their original spacing until the planter resumed a faster ground speed, at which time the seed spacing would increase accordingly. 
     Regardless of whether the seed dispensing apparatus  100  employs one or two endless belts, the apparatus  100  transports the seeds at controlled speeds for substantially the entire distance from the seed meter to the open furrow. The seeds are maintained in the order in which they are discharged from the meter, and a uniform spacing between adjacent seeds is maintained, despite any jostling or vibrating of row unit components due to surface irregularities along the agricultural field traversed by the planter, and despite any differences in the seeds themselves. The conveyor may be coupled synchronously with its associated seed meter, or driven independently to provide a conveyor speed independent of the speed of the associated seed meter. 
     Although only certain exemplary embodiments of the invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.