Abstract:
A seed meter for an agricultural seed planter, wherein the seed meter includes a rotatable disk assembly for a seed meter to dispense individual seeds at desired intervals. The rotatable disk comprises a seed disk including a plurality of circumferentially spaced seed apertures about the periphery operatively connected to a vacuum source, a substantially nonmagnetic backing disk member having a plurality of vacuum apertures and also in communication with the vacuum source, a resilient disk member adjacent and engageable with the nonmagnetic backing disk comprising a plurality of magnetic portions engageable with a magnetic source and adapted to occlude the seed aperture and disrupt communication with the vacuum source. The seed disk, substantially nonmagnetic backing disk member and resilient disk member are also rotatably mounted within a housing on a conduit. The vacuum source is operatively connected to the inside of the housing.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to seed metering mechanisms for dispensing individual seeds at a controlled rate into a seed furrow as the seed meter is advanced above and along the furrow and, more particularly, to a vacuum seed metering mechanism including a magnetic apparatus for separating the seeds from the vacuum seed meter. 
     BACKGROUND OF THE INVENTION 
     The precise planting of seeds is essential for achieving a field&#39;s maximum crop yield potential and profitability. Numerous agricultural planters are known in the art which utilize various types of seed metering devices designed to select and dispense individual seeds at desired intervals. 
     The most common types of seed meters being employed today are mechanical and vacuum seed meters. Mechanical seed meters typically removably secure the seeds to the meter through finger-like projections. Vacuum meters usually apply a vacuum to one side of a rotating disk containing concentric circular apertures thereby creating a negative pressure on the opposite sides of the disk. Vacuum seed meters are somewhat preferable to mechanical seed meters because they typically include fewer parts. With fewer parts, the farmer does not have as much to maintain and unsuccessful seed release due to a part failure is decreased. 
     Despite some of the advantages of vacuum seed meters, various reliability issues exist with the current vacuum seed meters. For example, the strong vacuum pressure typically required to sufficiently hold the seed within the aperture of the seed disk can result in the seeds not being timely discharged or smaller seeds or portions becoming lodged in the apertures. 
     A lack of proper maintenance of the seed meter or a farmer&#39;s failure to use the correct seed meter for a particular application contributes to the skipping or multiple dropping of individual seeds. Therefore, it would be advantageous to provide a vacuum seed meter device which requires little maintenance on the part of the farmer yet readily and timely discharges the seeds from the seed metering device. 
     SUMMARY OF THE INVENTION 
     The present invention provides a vacuum seed meter that includes a rotatable disk assembly for a seed meter to dispense individual seeds at desired intervals. 
     The rotatable disk includes a housing comprising a seed disk and defining an interior portion, the interior portion of the housing being in operable communication with a vacuum source. The seed disk includes a plurality of circumferentially spaced seed apertures about a periphery thereof, wherein the plurality of seed apertures is operatively connected to the vacuum source. 
     Also included as part of the rotatable disk assembly is a substantially nonmagnetic backing disk member disposed within the housing and in communication with the vacuum source and defining a plurality of vacuum apertures on a first surface thereof. 
     The rotatable disk assembly further comprises a resilient disk member adjacent to and engaging the backing disk at the first surface. The resilient disk member includes a plurality of magnetic portions wherein at least one of the plurality of magnetic portions is engageable with at least one of the plurality of spaced seed apertures of the seed disk when engaged with a magnetic source. Each of at least one of the plurality of magnetic portions is adapted to occlude the seed aperture and to disrupt communication between the at least one seed aperture and the vacuum source. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention. 
         FIG. 1  is a schematic front elevational view of a vacuum seed meter in accordance with a preferred embodiment of the invention; 
         FIG. 2  is a front view of a seed disk of the seed meter assembly of  FIG. 1 ; 
         FIG. 3  is a side view of the seed disk of  FIG. 2 ; 
         FIG. 4  is a side view of an enlarged portion of the seed disk of  FIG. 2 ; 
         FIG. 5  is a front view of a face plate of the seed meter assembly of  FIG. 1 ; 
         FIG. 6  is a side view of the face plate of  FIG. 5 ; 
         FIG. 7  is a front view of a resilient disk member of the seed meter assembly of  FIG. 1 ; 
         FIG. 8  is front view of an internal portion of the resilient disk member of  FIG. 7 ; 
         FIG. 9  is an enlarged view of a portion of one embodiment of the resilient disk member of  FIG. 7 ; 
         FIG. 10  is an enlarged view of a portion of one embodiment of the resilient disk member of  FIG. 7 ; 
         FIG. 11  is an enlarged view of a portion of one embodiment of the resilient disk member of  FIG. 7 ; 
         FIG. 12  is a front view of a substantially nonmagnetic backing disk of the seed assembly of  FIG. 1 ; 
         FIG. 13  is a side view of a vacuum seed meter in accordance with a preferred embodiment of the invention; 
         FIG. 14  is a schematic front elevational view of a vacuum seed meter in accordance with a preferred embodiment of the invention; 
         FIG. 15  is a side view of the seed meter assembly of  FIG. 14 ; 
         FIG. 16  is a side view of the vacuum seed meter assembly in accordance with a preferred embodiment of the invention; 
         FIG. 17  is a front view of a resilient disk member of the seed meter assembly of  FIG. 14 ; 
         FIG. 18  is a side view of the resilient disk member of  FIG. 17 ; 
         FIG. 19  is a front view of an internal portion of the resilient disk member of  FIG. 17 ; 
         FIG. 20  is a front view of a substantially magnetic portion associated with the seed meter assembly; and 
         FIG. 21  is a front view of a substantially nonmagnetic backing disk of the seed assembly of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While particular embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications and improvements may be made without departing from the true spirit and scope of the invention. 
     Shown in  FIG. 1  is a schematic front elevational view of a vacuum first seed meter assembly  100  in accordance with a preferred embodiment of the invention. First seed meter assembly  100  is designed to be used in association with a variety of different planting units, which include a seed hopper and furrow. Seed meter assembly  100  may have a housing  60  which includes a seed disk  20 , a face plate  30 , a resilient disk  40 , and a nonmagnetic backing disk  50 . During use, first seed meter assembly  100  rotates about a central axis  15 . Simultaneously, seeds may be dropped from a furrow through a seed inlet  10 . As the seed meter assembly  100  rotates, a vacuum is created within inner chamber  70  thereby causing a pressure difference between inner chamber  70  and the exterior of seed disk  20 . This pressure difference urges the individual seeds against a plurality of seed apertures  21 . As seed disk  20  travels past magnet  14  located in wall  13 , a portion of the resilient disk  40  that also travels past the magnet  14  is urged against a corresponding back portion of the seed disk  20 . When this occurs, the vacuum source to the individual plurality of seed apertures  21  is cut off thereby causing the individual seed to disengage from the seed aperture  21  and to exit through seed drop  11  to the ground for planting. After seed disk  20  is no longer in communication with magnet  14 , the resilient disk  40  is drawn back toward nonmagnetic backing disk  50  as a result of a pressure difference created by the vacuum source through a plurality of vacuum apertures  54 . As communication between the individual plurality of seed apertures  21  and the vacuum source is reestablished, a new seed is deposited at the seed aperture  21  as a result of the pressure differential. 
     As shown in  FIGS. 2-4 , the seed disk  20  is a circular disk having a central aperture  23  and a plurality of seed apertures  21  circumferentially spaced about edge  25 . In the preferred embodiment, seed disk  20  is composed of wear resistant material such as aluminum, steel or plastic. Although dimensions of the seed disk  20  may vary depending on various different planting needs, in the preferred embodiment, it has a general thickness of 0.0757 inches and the diameter at edge  25  through central axis  15  is preferably 10.5 inches. In comparison, the diameter of central aperture  23  is not limited to the dimensions associated with the seed disk  20  but instead corresponds to the diameter of conduit  17 . In the preferred embodiment, the diameter of central aperture  23  is approximately 2 inches. 
     The plurality of seed apertures  21  extend the entire width of seed disk  20  and are configured to hold seeds until disengagement occurs. The plurality of seed apertures  21  has a diameter of about 9 inches through the central axis  15 . Preferably, the diameter of each of the plurality of seed apertures  21  permits seeds to easily engage the plurality of seed apertures  21 . In one example, the diameter of each of the plurality of seed apertures is substantially the same and may be approximately 0.125 inches. Although the number of the plurality of seed apertures may vary depending on the dimensions and configurations of the seed meter assembly, in the preferred embodiment, the number of seed apertures  21  disposed at the seed disk  20  is 42. 
     Circumferentially aligned with the plurality of seed apertures  21  is a plurality of slots  22 . The slots  22  provide a means of agitating seeds within the seed hopper. In some instances, the plurality of slots  22  may become blocked with loose debris. As each of the plurality of slots  22  rotate, they pass brush  12  which may remove any debris contained within the slot such as seed particles. In the preferred embodiment, the diameter of each of the plurality of slots  22  is approximately 0.25 inches and the length is approximately 0.64 inches. As shown in detail in  FIG. 3 , each slot  22  extends a depth into the seed disk  20  that is less than the width of the seed disk  20 . The plurality of slots  22 , therefore, do not extend through the entire width of seed disk  20 . In the preferred embodiment, this depth distance for each of the plurality of slots  22  is approximately 0.11 inches. Each of the plurality of slots  22  is spaced a distance from each plurality of seed apertures  21 . In the preferred embodiment, the slots  22  and seed apertures  21  are spaced a distance of approximately 0.20 inches. 
     The number, placement and dimension of the plurality of seed apertures and slots may vary depending on the type of seeds being planted and size of seed meter assembly without departing from the spirit of the invention. 
     As shown in  FIGS. 5-6 , the face plate  30  is a circular disk including edge  32 , central aperture  33 , and a plurality of mounting apertures  31 . The diameter of face plate  30  from edge  32  to central axis  15  is approximately 3.75 inches. The thickness of face plate  30  in the preferred embodiment is approximately 0.1 inches. The plurality of mounting apertures  31  are circumferentially spaced about edge  32  and extend through the entire width of face plate  30 . In the preferred embodiment, the diameter of the plurality of mounting apertures through central axis  15  is approximately 2.88 inches. In the preferred embodiment, the diameter of central aperture  33  is approximately 2 inches and generally corresponds with the diameter of conduit  17 . These dimensions may vary without departing from the spirit of the invention. 
     Resilient disk member  40  shown in  FIGS. 7-11  may be composed of three different layers. A first layer  42  and a second layer  45  are substantially identical, elastomeric and preferably composed of rubber. The first layer  42  includes a first edge  41  and a first central aperture  43 . The second layer includes a second edge  46  and a second central aperture  47 . A plurality of substantially magnetic portions  44  is disposed between first layer  42  and second layer  45 . The first layer  42 , the plurality of substantially magnetic portions  44 , and the second layer  45  are bonded together or cured to form resilient disk member  40  by means known in the art. In the preferred embodiment, the diameters of first and second layers,  42  and  45 , respectively, at first and second edges,  41  and  46 , respectively, are approximately 10 inches. The diameter of first and second layers,  42  and  45 , respectively, at first and second central apertures,  43  and  47 , respectively is approximately 2 inches. 
     The number of the plurality of substantially magnetic portions  44  preferably equals the number of plurality of seed apertures  21  on seed disk  20 . Each of the plurality of substantially magnetic portions  44  is arranged between first and second central apertures,  43  and  47 , respectively, and first and second edge  41  and  46 , respectively. In different embodiments, each of the plurality of substantially magnetic portions  44 , as shown as single line  48  in  FIG. 8 , is composed of more than one magnetic portion. Various embodiments of single line  48  are shown in  FIG. 9  through  FIG. 11 . As shown in  FIG. 9 , line  48  comprises three individual magnetic strips,  44   a ,  44   b  and  44   c , wherein each strip extends from second central aperture  47  to second edge  46 . As shown in  FIG. 10 , line  48  includes three individual magnetic strips,  44   d ,  44   e  and  44   f , wherein only strip  44   e  extends all the way between second central aperture  47  and second edge  46 .  FIG. 11  is a representation of line  48  wherein it includes four individual magnetic strips,  44   g ,  44   h ,  44   i  and  44   j , wherein each strip extends from second central aperture  47  to second edge  46 . In a seed disk with approximately 42 individual seed apertures, the number of strips as shown as line  48  is preferably between three and four. The arrangement of strips as shown in  FIGS. 9-11  is merely by way of example and other arrangements known in the art may suffice without departing from the spirit of the invention. 
     The nonmagnetic backing member  50  is shown in  FIG. 12  and includes central aperture  53 , edge  51 , and a plurality of vacuum apertures  54 . The plurality of vacuum apertures  54  is circumferentially spaced around central axis  15  and between central aperture  53  and edge  51 . The vacuum apertures  54  are used in maintaining the pressure differential associated with the seed meter assembly  100 . At a time when magnet  14  is not magnetically coupled to the plurality of substantially magnetic portions  44 , the vacuum apertures  54  provide a pressurization that urges the resilient disk member  40  away from the seed disk  20  toward the nonmagnetic backing disk  50 . This movement permits the seeds to engage the plurality of seed apertures  21 . 
     The nonmagnetic backing member  50  is preferably nonferrous and its dimensions may vary without departing from the spirit of the invention. In the preferred embodiment, the diameter of nonmagnetic backing disk  50  at edge  51  may be substantially the same as the diameter of the resilient disk member  40 , which is approximately 10 inches. Each of the plurality of vacuum apertures  54  may be disposed at a location equidistant from edge  51  and axis  15 . These vacuum apertures  54  may have a diameter of approximately 0.5 inches whereas the diameter of the plurality of vacuum apertures  54  to the axis  15  may be approximately 5 inches. The diameter of central aperture  53  is approximately 2 inches. 
       FIG. 13  shows a cut-through side view of the assembled components of a seed disk assembly. In this embodiment, the seed disk assembly comprises first seed meter assembly  100  and second seed meter assembly  1000 . First seed meter assembly  100  and second seed meter assembly  1000  are rotatably mounted on conduit  17 , wherein first seed meter assembly  100  and second seed meter assembly  1000  face each other. In the preferred embodiment, the first seed meter assembly  100  and second seed meter assembly  1000  are spaced approximately 2.25 inches from each other and the distance between the outer edges of first seed meter assembly  100  and second meter assembly  1000  is approximately 4 inches. In additional embodiments, first seed meter assembly  100  and second seed meter assembly  1000  may face away from each other when mounted on conduit  17 . 
     The first seed meter assembly  100  includes a housing  60 . Within housing  60 , seed disk  20  is adjacent face plate  30 , which is adjacent resilient disk member  40 , which is adjacent nonmagnetic backing disk  50 . Housing  60  secures these elements in the proper assembly about conduit  17 . Face plate  30 , resilient disk member  40  and nonmagnetic backing disk  50  are contained within inner chamber  70 . 
     The dimensions of the first seed meter assembly  100  may vary depending on different configurations of the assembly. In the preferred embodiment, the width of first seed meter assembly  100  is approximately 0.83 inches. In the preferred embodiment, the width of seed disk  20  is approximately 0.19 inches and the distance between seed disk  20  and resilient disk member  40  is approximately 0.14 inches. As discussed before, however, this distance may vary during operation of the seed meter assembly. In the preferred embodiment, the width of resilient disk member  40  is approximately 0.13 inches and the width of nonmagnetic backing disk  50  is approximately 0.09 inches. In the preferred embodiment, the distance between nonmagnetic backing disk  50  and one end of inner chamber  70  is approximately 0.19 inches. In the preferred embodiment, the distance from the bottom of housing  60  and inner chamber  70  is approximately 0.10 inches. In the preferred embodiment, the distance from the bottom of inner chamber  70  and resilient disk member  40  and nonmagnetic backing disk  50  is approximately 0.13 inches. 
     Second seed meter assembly  1000  is assembled in a similar fashion as first seed meter assembly  100 . Second seed meter assembly  1000  comprises second seed disk  200 , second face plate  300 , second resilient disk member  400 , second nonmagnetic backing disk  500 , and second housing  600 . In the preferred embodiment, second seed disk  200  is similar to seed disk  20 , second face plate  300  is similar to face plate  30 , second resilient disk member  400  is similar to resilient disk member  40 , second nonmagnetic backing disk  500  is similar to nonmagnetic backing disk  50 , second housing  600  is similar to housing  60  and second inner chamber  700  is similar to inner chamber  70 . Additionally, in the preferred embodiment, the components of second seed meter assembly  1000  are arranged in a similar fashion as first seed meter assembly  100 . As such, the dimensions discussed above are similar for both first seed meter assembly  100  and second seed meter assembly  1000 . 
     First vacuum tube  18  and second vacuum tube  19  reside within conduit  17  wherein second vacuum tube  19  is contained within first vacuum tube  18 . First vacuum tube  18  and second vacuum tube  19  are connected to a vacuum source (not shown). When assembled, first vacuum tube  18  extends into inner chamber  70  and second vacuum tube  19  extends into second inner chamber  700 . In the preferred embodiment, conduit  17 , first vacuum tube  18  and second vacuum tube  19  are centered about central axis  15 . In order to allow first vacuum tube  18  and second vacuum tube  19  to be in communication with inner chamber  70  and second inner chamber  700 , respectively, conduit  17  may include apertures. In the preferred embodiment, the diameter of conduit  17  is approximately 2 inches. The diameter of both first vacuum tube  18  and second vacuum tube  19  may vary as long as a vacuum tight seal is created between first chamber  70  and second chamber  700 , respectively. 
     Individual seeds are removed from the plurality of seed apertures  221  on second seed meter assembly  1000  through use of a magnet as described above in reference to first seed meter assembly  100 . 
     The rotation of the seed meter assembly is controlled by a motor. In a preferred embodiment, an electric registry-type motor may be included. The registry motor allows the rotation of the seed meter assembly, and thus release of the individual seeds, to be finely and precisely controlled. 
     A vacuum seed meter assembly  1100  in accordance with a preferred embodiment of the invention is shown in  FIGS. 14-16 . Vacuum seed meter assembly  1100  may include a seed disk  1120 , a resilient disk member  1140 , a nonmagnetic backing member  1150 , a chamber  1170 , and a stationary holder  1102  operably connected to one another. A housing  1160 , associated with the seed meter assembly  1100 , may include the seed disk  1120 , the resilient disk member  1140 , the nonmagnetic backing member  1150 , and the chamber  1170 . In some embodiments, the seed disk  1120  may be similar to seed disk  20  described in  FIGS. 2-4 , the nonmagnetic backing disk  1150  may be similar to nonmagnetic backing disk  50  described in  FIG. 12 , and the resilient disk member  1140  may be similar to resilient disk member  40  described in  FIGS. 7-11 . Vacuum seed meter assembly  1100  may be used in association with a variety of different planting units, which include a seed hopper and furrow. During use, the vacuum seed meter assembly  1100  rotates relative to the stationary holder  1102  having associated magnetic characteristics. 
     Stationary holder  1102  is spaced a distance from the housing  1160  but remains magnetically connectable with the resilient disk member  1140 . Stationary holder  1102  has an interior edge  1105  having at least one magnet  1106  attached thereon. In one embodiment, stationary holder  1102  includes at least two magnets  1106  and  1107  disposed at the interior edge  1105 . The at least two magnets  1106  and  1107  may be magnetically coupled to a magnetic portion associated with the resilient disk member  1140 . 
     During use, the vacuum seed meter assembly  1100  rotates causing seeds  1101  to engage the seed disk  1120  against a plurality of seed apertures  1121 . In one embodiment, seeds may be dropped from a furrow through a seed inlet for disposal at the plurality of seed apertures  1121 . As the seed meter assembly  1100  rotates, a vacuum is created within inner chamber  1170  thereby causing a pressure difference between inner chamber  1170  and the exterior of the seed disk  1120 . This pressure difference urges the individual seeds against a plurality of seed apertures  1121 . As the seed disk  1120  travels past magnets  1106  and  1107 , a portion of the resilient disk member  1140  that also travels past the magnets is urged against a corresponding back portion of the seed disk  1120 . When this occurs, the vacuum source to the individual plurality of seed apertures  1121  is cut off thereby causing the individual seed to release from the corresponding seed aperture  1121 . After release, the seed may exit the seed meter assembly  1100  where it may be used for planting. After the seed disk  1120  is no longer in communication with magnets  1106  and  1107 , the resilient disk member  1140  is drawn back toward the nonmagnetic backing disk  1150  as a result of a pressure differential created by the vacuum source through a plurality of vacuum apertures  54 . Moreover, the communication between the individual plurality of seed apertures  1121  and vacuum source is reestablished and a new seed is deposited against the seed aperture as a result of the pressure differential 
     The seed disk  1120  as shown in  FIGS. 14-15  is a circular disk having a central aperture  1123  covered by plate  1124  and a plurality of seed apertures  1121  circumferentially spaced about edge  1125 . In the preferred embodiment, seed disk  1120  is composed of wear resistant material such as aluminum, plastic or nonferrous material. Although dimensions of the seed disk  1120  may vary depending on various different planting needs, in the preferred embodiment, it has a general thickness of 0.0757 inches and the diameter at edge  1125  through central axis  1115  is preferably 10.5 inches. In comparison, the diameter of central aperture  1123  is not limited to the dimensions associated with the seed disk  1120  but instead is determined by the size of the diameters of other corresponding central apertures as well as the rotational shaft used to drive the assembly. In the preferred embodiment, the diameter of central aperture  1123  is approximately 2 inches. 
     The plurality of seed apertures  1121  extend the entire width of seed disk  1120  and are configured to hold seeds until disengagement occurs. The plurality of seed apertures  1121  has a diameter of about 9 inches through the central axis  1115 . Preferably, the diameter of each of the plurality of seed apertures  1121  permits seeds to easily engage the plurality of seed apertures. In one example, the plurality of seed apertures  1121  is substantially the same and may be approximately 0.125 inches. Although the number of the plurality of seed apertures may vary depending on the dimensions and configurations of the seed meter assembly, in the preferred embodiment, the number of seed apertures  1121  disposed at the seed disk  1120  is 42. 
     Circumferentially aligned with the plurality of seed apertures  1121  is a plurality of slots  1122 . The slots  1122  provide a means of agitating seeds within the seed hopper. In the preferred embodiment, the diameter of each of the plurality of slots  1122  is approximately 0.25 inches and the length is approximately 0.64 inches. Similar to the example shown in  FIG. 3 , each slot  1122  extends a depth into the seed disk  1120  that is less than the width of the seed disk  1120 . The plurality of slots  1122 , therefore, do not extend through the entire width of seed disk  1120 . In the preferred embodiment, this depth distance for each of the plurality of slots  1122  is approximately 0.11 inches. Each of the plurality of slots  1122  is spaced a distance from each plurality of seed apertures  1121 . In the preferred embodiment, the slots  1122  and seed apertures  1121  are spaced a distance of approximately 0.20 inches. 
     The number, placement and dimension of the plurality of seed apertures and slots may vary depending on the type of seeds being planted and size of seed meter assembly without departing from the spirit of the invention. 
     Resilient disk member  1140  shown in  FIGS. 17-19  may be composed of three different layers. A first layer  1142  and a second layer  1145  are substantially identical, elastomeric and preferably composed of rubber. The first layer  1142  includes a first edge  1141  and a first central aperture  1143 . The second layer includes a second edge  1146  and a second central aperture  1147 . A plurality of substantially magnetic portions  2000  is disposed between the first layer  1142  and the second layer  1145 . First layer  1142 , the plurality of substantially magnetic portions  2000 , and second layer  1145  are bonded together or cured to form resilient disk member  1140  by means known in the art. The diameter of first and second layers,  1142  and  1145 , respectively, at first and second edges,  1141  and  1146 , respectively, are approximately 10 inches. The diameter of first and second layers,  1142  and  1145 , respectively, at first and second central apertures,  1143  and  1147 , respectively is approximately 2 inches. 
     In one embodiment, each individual magnet portion  2000  includes a top edge  2010 , bottom edge  2020 , a first side edge  2030 , and a second side edge  2040 . Both the top edge  2010  and bottom edge  2020  have notches  2060  and  2050  that may be used during the manufacturing process. The number of substantially magnetic portions  2000  preferably equals the number of plurality of seed apertures  1121  on seed disk  1120 . Each of the plurality of substantially magnetic portions  2000  is arranged between first and second central apertures,  1143  and  1147 , respectively, and first and second edge  1141  and  1146 , respectively. The arrangement of magnets as shown in  FIGS. 18-19  is merely by way of example and other arrangements known in the art may suffice without departing from the spirit of the invention. 
     The substantially magnetic portions  2000  and magnets  1106  and  1107  of the stationary holder  1102  may be coupled via a magnetic force. During rotation of the resilient disk member  1140 , the substantially magnetic portions  2000  may align with magnets  1106  or  1107 . During alignment, the attractive magnetic force between magnets  1106  or  1107  and at least one of the substantially magnetic portions  2000  causes the resilient disk member  1140  to move toward the stationary holder  1102 . This movement may cause the resilient disk member  1140  to abut against a back side of the seed disk  1120  so as to occlude the plurality of seed apertures  1121 . This occlusion causes a brief disruption of suction force being applied to the seeds  1101  thereby causing them to disengage from the seed apertures  1121  and the seed disk  1120 . 
     The nonmagnetic backing member  1150  is shown in  FIG. 21  and includes central aperture  1153 , edge  1151 , and a plurality of vacuum apertures  1154 . The plurality of vacuum apertures  1154  is circumferentially spaced around central axis  1115  and between central aperture  1153  and edge  1151 . The vacuum apertures  1154  are used in maintaining the pressure differential associated with the seed meter assembly  1100 . At a time when stationary holder magnets  1106  and  1107  are not magnetically coupled to the plurality of magnetic portions  2000 , the vacuum apertures  1154  provide a pressurization that urges the resilient disk member  1140  away from the seed disk  1120  toward the nonmagnetic backing disk  1150 . This movement permits the seeds to engage the plurality of seed apertures  1121 . 
     The nonmagnetic backing member  1150  is preferably nonferrous and its dimensions may vary without departing from the spirit of the invention. In the preferred embodiment, the diameter of nonmagnetic backing disk  1150  at edge  1151  may be substantially the same as the diameter of the resilient disk member  1140 , which is approximately 10 inches. Each of the plurality of vacuum apertures  1154  may be disposed at a location equidistant from edge  1151  and axis  1115 . These vacuum apertures  1154  may have a diameter of approximately 0.5 inches whereas the diameter of the plurality of vacuum apertures  1154  to the axis  1115  may be approximately 5 inches. The diameter of central aperture  1153  is approximately 2 inches. 
     Pressurization of the vacuum seed meter assembly  1100  may include any method generally known in the art. In one example, the seed meter assembly  1100  shown in  FIG. 15  may be connected to a vacuum chamber  1110  and a vacuum source by a vacuum connector  1108  to create the pressure differential in the housing  1160 . The configuration of the vacuum chamber  1110  and the vacuum source may be of the type generally known in the art. 
     A rotational shaft may connect to the housing  1160  and be configured to rotate the seed disk  1120 . In one embodiment, at least one bearing may be operably connected to the rotational shaft to effect rotation of the seed disk  1120 . In one embodiment, the rotational shaft is connected to central aperture  1123  of the seed disk, first central aperture  1143  and second central aperture  1147  of the resilient disk member  1140 , and central aperture  1153  of the nonmagnetic backing disk  1150 . This configuration permits the rotational shaft to rotate the vacuum seed meter assembly  1100 . 
     The rotational shaft may be driven by any known means in the art. In one example, the rotation of the seed meter assembly is controlled by a motor. In a preferred embodiment, an electric registry-type motor may be included. The registry motor allows the rotation of the seed meter assembly, and thus release of the individual seeds, to be finely and precisely controlled. In another example, the external vacuum source is not only used to create the pressure differential within the housing, but is also operably connected and configured to drive the rotation of the rotational shaft as is generally known in the art.