Abstract:
An improved seed metering wheel assembly is provided to deliver a substantially constant flow of seed to a downstream treating device or the like, without any substantial surging of seeds. The seed metering wheel assembly includes an axially rotatable metering wheel having a plurality of strategically sized and arranged seed metering openings therethrough, arranged in circular arrays of differently sized metering openings. In another embodiment, the seed metering wheel includes a central hub section and an outermost rib, with a series of ribs between the hub section and rim, which lie along respective non-diameter chords. Incoming seed is delivered from a seed hopper outlet by gravitation to the metering wheel, which preferably provides a substantially constant open area while preventing wholly unobstructed flow of seeds.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of application Ser. No. 13/830,083, filed Mar. 14, 2013, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is concerned with improved seed metering wheel assemblies, which substantially eliminate surges of seed during operation of a seed treater. More particularly, the invention is concerned with such wheel assemblies, and corresponding methods, wherein a rotatable metering wheel assembly is located beneath a seed hopper and has strategically sized and oriented metering openings therethrough. The openings are preferably of different sizes and are arranged in circular arrays so that a substantially constant volumetric and weight output flow of seeds is achieved. 
         [0004]    2. Description of the Prior Art 
         [0005]    Coating of agricultural seeds is a common practice in sophisticated farming operations. Thus, seeds have been coated with herbicides, fungicides, absorbents, fertilizers, or other chemicals. Generally, specialized seed treaters are used for these purposes and include an inlet hopper, a seed coating device, and a downstream rotatable dryer. A seed metering device is usually provided between the seed hopper and seed coating device, in an effort to give a substantially constant output flow of seeds to the coating device. However, some prior seed metering devices are prone to surging and inconsistent seed flow, which can lead to over- and undercoating of seeds. The problem of seed surging is significant because the usage rate of coating materials normally does not vary once the treater reaches a steady state condition. Accordingly, when a surge occurs, the quantity of seed delivered to the coater is not matched with the supply and application rates of the coating chemicals. Therefore, the seed treater necessarily produces substantial quantities of under-coated seeds. 
         [0006]    U.S. Pat. No. 4,465,017 describes a seed coating device having a typical seed metering wheel of spoked design in the form of a circular, axially rotatable wheel having a series of radial spokes extending from a central hub to the rim of the wheel. Metering wheels of the type described in the &#39;017 patent are subject to surging in instances where an unobstructed flow path is presented, which allows a greater rate of seed flow to the downstream coating apparatus. 
         [0007]    In order to ameliorate the effects of seed surging, downstream flow-equalizing devices have been employed, which significantly improve the operation of simple seed wheels. However, these accessories add expense and complexity to the metering equipment. 
         [0008]    There is accordingly a need in the art for an improved seed metering wheel assembly which is capable of delivering substantially constant flows of seed over a given time period by the essential elimination of undesirable seed surging, without the need for downstream flow equalization devices. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention overcomes the problems outlined above, and provides improved seed metering wheel assemblies operable to deliver substantially constant flows of seed over a seed treatment time period of at least about 30 minutes. Broadly, the seed treaters of the invention each include a hopper assembly including a lower seed outlet opening of predetermined shape and size, so that the hopper assembly is operable to hold a supply of seeds and to deliver by gravitation quantities of the seed to the seed outlet opening over the time period. An axially rotatable seed metering wheel assembly is located beneath the seed outlet opening of the hopper and is oriented to receive the quantities of seed and to create a substantially uniform output flow of the seeds. The rotatable metering wheel forming a part of the overall assembly includes a plurality of seed metering openings therethrough and defined by corresponding rib sections. In one embodiment, the rib sections and openings are oriented to present a substantially constant open area beneath the hopper seed outlet opening over the coating period, with at least certain portions of the seed metering opening-defining ribs extending across the seed outlet opening over substantially all of the coating period, in order to prevent wholly unobstructed flow of seeds from the seed outlet opening through the seed metering wheel assembly. Advantageously, at least certain of the seed metering openings are of a size different than the size of others of the seed metering openings. The seed metering openings may be located in a plurality of individual circular arrays each having identically sized openings within the array. Alternately, the seed metering wheel comprises a central hub section, a circular rim outboard of said central hub section, and a series of ribs extending between said central hub section and said rib and defining through-openings, said ribs lying along respective, spaced apart, non-diameter chord lines. 
         [0010]    The invention also provides methods for metering quantities of seed by delivering through gravitation quantities of seed from a seed outlet opening to a metering station having a seed metering wheel in accordance with the invention. At the metering station, successive quantities are passed through a series of seed metering openings defined by corresponding rib sections and rotating about an axis, so that the rib sections and seed metering openings present a substantially constant open area during seed metering, and with at least certain portions of the seed metering opening-defining ribs extending across said seed metering openings in order to prevent wholly unobstructed flow of seeds from the outlet opening and through the seed metering openings. 
         [0011]    As used herein, a “substantially constant open area” refers to maintaining, at substantially all times, a predetermined open area A, and up to plus or minus 10% of A (more preferably plus or minus 5%), through the seed metering wheel assembly. For example, if a predetermined open area is 10 square inches, a substantially constant area would be from 9-11 square inches. In like manner, a “substantially constant” flow of seeds from the seed metering wheel assembly would encompass a preselected flow rate F and plus or minus 10% of F (more preferably plus or minus 5%). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a seed treater apparatus having the seed metering wheel assembly of the invention mounted thereon; 
           [0013]      FIG. 2  is a perspective view of the seed metering wheel assembly and seed delivery shoot forming a part of the seed treater apparatus; 
           [0014]      FIG. 3  is a plan view of the apparatus illustrated in  FIG. 2 ; 
           [0015]      FIG. 4  is a vertical sectional view taken along the line  4 - 4  of  FIG. 3 ; 
           [0016]      FIG. 5  is a vertical sectional view taken along the line  5 - 5  of  FIG. 3 ; 
           [0017]      FIG. 6  is a top perspective view of the preferred seed metering wheel assembly of the invention; 
           [0018]      FIG. 7  is a bottom perspective view of the seed metering wheel assembly illustrated in  FIG. 6 ; 
           [0019]      FIG. 8  is an exploded perspective view of the seed metering wheel assembly; 
           [0020]      FIG. 9  is an exploded perspective view of the apparatus depicted in  FIGS. 2-5 ; 
           [0021]      FIG. 10  is a perspective view of another seed metering wheel design in accordance with the invention; 
           [0022]      FIG. 11  is a plan view of the seed metering wheel of  FIG. 10 ; 
           [0023]      FIG. 12  is an upper, perspective, exploded view depicting the components of the seed metering wheel of  FIG. 10 ; 
           [0024]      FIG. 13  is a lower, perspective, exploded view depicting the components of the seed metering wheel of  FIG. 10 ; 
           [0025]      FIG. 14  is a vertical sectional view taken along the line  14 - 14  of  FIG. 11 ; 
           [0026]      FIG. 15  is a vertical sectional view taken along the line  15 - 15  of  FIG. 11 ; 
           [0027]      FIG. 16  is a vertical sectional view taken along the line  16 - 16  of  FIG. 11 ; and 
           [0028]      FIG. 17  is a top view illustrating the seed metering wheel of  FIG. 10  within the overall metering assembly. 
       
    
    
     DETAILED DESCRIPTION 
     Embodiment of FIGS.  1 - 9  with Seed Metering Wheel  100   
       [0029]    Turning now to the drawings, a complete seed treater  10  is depicted in  FIG. 1  and is equipped with a seed metering wheel assembly  12  in accordance with the invention. Generally speaking, the treater  10  is designed to receive incoming quantities of seed, to apply one or more chemicals onto the surfaces of the seeds, and to thereupon dry the seeds. The illustrated seed treater  10  has the assembly  12  which directs seed into an atomizer  14  where the seeds are coated with chemical(s). The preferred atomizer is described in U.S. Pat. Nos. 6,551,402 and 6,783,082, incorporated by reference herein. The coated seeds are then dried within a downstream rotating drum dryer  16 , and the finished seeds are delivered by way of outlet  18  for storage or use. 
         [0030]    The seed metering wheel assembly  12  broadly includes an uppermost hopper assembly  20 , an intermediate metering assembly  22 , a lower plate assembly  23 , and a lowermost delivery chute  24 , which is secured to the inlet end of atomizer  14 . 
         [0031]    The hopper assembly  20  includes a housing  26  having an upright tubular sidewall  27 , circular upper and lower connection flanges  28  and  36 , a pair of opposed vents  32 , and a series of removable access plates  54 . A unitary seed-receiving hopper  34  having a connection flange  36  is positioned within the confines of housing  26 , such that the flanges  36  and  30  mate and are connected via fasteners (not shown). The hopper  34  has an arcuate center line apex  38  with identical, downwardly extending, arcuate wall sections  40  and  42  each equipped with an identical, generally triangularly-shaped seed outlet opening  44  or  46 ; the latter have downwardly extending, defining wall structures  48  or  50 . If desired, a tubular extension  55  ( FIG. 1 ) may be attached to the upper end of housing  26  in order to increase the effective volume of the hopper assembly  20 . 
         [0032]    The seed metering assembly  22  is positioned below hopper assembly  20  and includes a stationary, tubular housing  56  with upper and lower connection flanges  58  and  60 . The upper flange  58  of housing  56  mates with lower flange  30  of assembly  20 , with appropriate fasteners serving to connect the flanges. The housing  56  supports a stationary channel  62 , which in turn supports an electrical drive motor  64  and gear box  66 . The channel  62  also supports a pair of outboard brackets  68  and  70  at the central region thereof. A pair of identical, generally triangular weldments  71  are respectively connected to the brackets  68  and  70  and extend outwardly and are supported by the housing  56 . The weldments  71  each include a pair of diverging box sidewalls  72 ,  74  and  80 ,  82 , as well as an outboard spacer  75  or  83 , and fasteners  76 ,  78  or  84 ,  86 . Seed sensors  88  and  90  are respectively connected with box sidewalls  72  and  80 . A lowermost, radially extending brush  92  is secured to sidewall  74 , and an identical brush  94  is secured to sidewall  82 . It will be observed that the weldments  71  each define a substantially triangular through-opening  96  or  98 , and are respectively in registry with the seed outlet openings  44  and  46  of hopper assembly  20 . It will thus be appreciated that the openings  96 ,  98  are seed entrance openings for the metering assembly  22 . 
         [0033]    The overall metering assembly  22  also includes an axially rotatable metering wheel  100 , which is situated within the confines of housing  56 . The wheel  100  is of composite design (see  FIG. 8 ) and has a series of interconnected, apertured plates, namely an upper synthetic resin wheel plate  102 , an intermediate stainless steel reinforcing plate  104 , and a lower synthetic resin plate  106 . A circumscribing, upwardly extending seed retaining ring  108  surrounds the apertured plates and extends above the upper surface of plate  102 . The interconnected plates  102 - 106  have a central, hexagonal drive opening  109  and a series of seed metering openings  110  therethrough. In detail, the openings  110  are arranged in a total of three circular arrays  112 ,  114 , and  116 . The inner array  116  has a plurality of identical, truncated triangular through-openings  118 ; the intermediate array  114  has a plurality of identical, elongated, arcuate openings  120 , which are in staggered relationship relative to the openings  118 . Finally, the outer array  112  has another series of identical, elongated arcuate openings  122 , which are staggered relative to the openings  120  of the intermediate array. It will further be observed that the openings  118 ,  120 , and  122  are each defined by circumscribing rib sections  118   a ,  120   a , and  122   a.    
         [0034]    The metering wheel  100  is rotated in a clockwise direction, as viewed in  FIG. 4 , by means of the motor  64  and gear box  66 . The box  66  has an elongated, hexagonal, vertically extending, rotatable drive shaft  124  with a lowermost, downwardly extending threaded shank  124   a  extending below the wheel  100 . The shaft  124  and hub  125  serve to rotate the wheel  100 , with the shaft  124  received within the central drive opening  109 . The operation of motor  64  is controlled by means of conventional wiring including electrical leads  126  and junction box  128  connected to a digital controller (not shown). 
         [0035]    Plate assembly  23  is stationary and includes an upper metallic wear plate  130  which engages the lower surface of wheel  100 , a synthetic resin foam support pad  132 , and a lowermost metallic floor plate  134 . The plates  130  and  132  have identical, opposed, outwardly diverging slots  136  and  138 , whereas plate  134  has similarly configured through-openings  140 . The wear plate  130  has a pair of downwardly extending flanges  131  adjacent the edges of openings  136 , which direct seed downwardly as the seed exits the assembly  23 . The assembly  23  is mounted on shank  124   a , and an elongated bearing plate  142 , washer  144 , and nut  146  are used to mount the assembly  23 . 
         [0036]    The delivery chute  24  is generally frustoconical and has an uppermost connection flange  150 , a tapered hollow body section  152  and a lowermost connection flange  154 . The flange  150  is connected to the underside of the plate assembly  23  (with optional use of a spacer ring  156 ) by means of elongated connectors  158 . 
         [0037]    As is evident from the foregoing description, the seed metering wheel assembly  12  provides a hopper for receiving seeds to be treated, with the seeds flowing by gravitation through the seed outlet openings  44  and  46 , and then through the underlying weldment openings  96  and  98  where the seeds encounter the metering wheel  100 . After passage through the metering wheel  100 , the seeds pass through the stationary openings  136 ,  138 , and  140  of plate assembly  23 , and are finally directed into and through the delivery chute  24  to the atomizer  14  of treater  10 . 
         [0038]    The passage of seed through the metering wheel  100  is of prime importance. That is, as the wheel  100  rotates, the especially designed and configured seed metering openings  118 ,  120 , and  122 , and the corresponding opening-defining rib sections  118 ,  120   a , and  122   a  continually present a substantially constant open area. That is to say, at virtually every each instant over a given time period, the wheel  100  gives an effective through-opening, which is of substantially constant area. Furthermore, owing to the preferred, differently sized openings  118 - 122 , the staggered orientation thereof, and the locations of the defining rib sections  118   a - 122   a , at no instant is there a wholly unobstructed seed flow path through the wheel  100 . As such, the tendency of prior spoke-type seed metering wheels to cause a buildup of seed, followed by presentation of a completely unobstructed seed flow path with consequent surging or “dumping” of seed, is substantially eliminated. The presence of the stationary brushes  92  and  94  assists in the desirable operation of the metering wheel  100 , by acting as a leveling device in order to successively level the upper surfaces of quantities of seeds retained by the ring  108 , so that substantially constant seed weights are present at the inlet face of the metering wheel  100 . Consequently, the seed metering wheel assembly  12  of the invention provides a substantially constant weight and volumetric flow of seed to the downstream seed treater. 
       Embodiment of FIGS.  10 - 17  with Seed Metering Wheel  200   
       [0039]    Turning to  FIGS. 10-16 , a seed metering wheel  200  is depicted. The wheel  200  has a different design as compared with the previously described seed metering wheel  100 , and is configured for use within the overall seed metering assembly  22 . The wheel  200  is a simpler design which can be manufactured at a lower cost as compared with wheel  100 . 
         [0040]    In particular, the wheel  200  is of composite design, comprising upper and lower, interconnected, synthetic resin wheel plates  202  and  204 . The interconnected plates  202 ,  204  cooperatively define a central hub  206  having a hexagonal drive opening  208  therethrough. As illustrated in  FIG. 10 , a rotatable drive shaft  210 , identical with previously described shaft  124 , extends into the opening  208  in order to rotate wheel  200  by means of motor  64  and gear box  66 . To this end, a hub plate  212  also forms a part of the drive assembly for the wheel  200 . 
         [0041]    The overall wheel  200  includes an outermost rim  214 , a total of eight elongated ribs  216  which extend from central hub  206  to rim  214 , and a circular reinforcing ring  218  between hub  206  and rim  214 . It will be observed that the ribs  216  lie along respective, non-diameter chord lines  220  ( FIG. 11 ) which are equally spaced about the wheel  200 . In this fashion, the wheel  200  presents a series of eight somewhat triangular inner openings  222  between central hub  206  and reinforcing ring  218 , and eight larger, generally quadrate openings  224 , each outboard of an opening  222  and located between ring  218  and rim  214 . 
         [0042]    In more detail, it will be seen that plates  202  and  204  are in face-to-face contact, and are interconnected by means of screws  226 . As best illustrated in  FIGS. 13-16 , the lower wheel plate  204  has a reduced thickness downwardly extending circular contact lip  228  forming apart of rim  214 ; likewise, the lower extents of the ribs  216  are of reduced thickness. Stated otherwise, the thickness of the lower edge of the lower plate  204  is thinner than the thickness of the upper edge of the upper plate  202 . These features serve to reduce the friction between the wheel  200  and the underlying structure of assembly  22 , while also providing sufficient mechanical strength for the wheel. 
         [0043]    As explained previously, the wheel  200  is an alternate design, which is fully compatible with the components of assembly  22 . This is best illustrated in  FIG. 17 , which depicts the weldments  71  defining the through-openings  96 ,  98  serving as seed entrance openings for the wheel  200 . 
         [0044]    The operation of wheel  200  is exactly as previously described in connection with wheel  100 . During such operation. At virtually every instant over a given period of time, the wheel  200  presents effective through-openings of substantially constant area, and in no instance is there a wholly unobstructed seed flow path through the wheel  200 .