Abstract:
A flat seed disk is provided with a series of circumferentially arranged seed retaining protrusions providing seed retention at locations offset axially from the remainder of the disk. The offset allows the seed to fall in the correct location of the seed tube to reduce unwanted seed bounce and provide better seed delivery to the ground and better seed spacing as compared to flat disks without the offset. In one embodiment, the protrusions have seed retaining faces opening generally in the direction of disk rotation. In other embodiments, the faces are angled away from the direction of rotation to reduce interference between released seed and adjacent protrusions, and trailing radial ledges can be provided to enhance seed retention.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention is directed to a rotatable seed disk for a vacuum seed meter having offset for improved seed trajectory.  
       BACKGROUND OF THE INVENTION  
       [0002]     Seed meters are used by agricultural seeding machines to control the rate at which seed is applied to a field. Air pressure meters use either positive or negative air pressure to direct seed to apertures formed in a rotating seed disk and to hold the seed in the apertures until a preselected release point is reached. Sealing or cut-off structure on the seed meter typically is used to isolate a portion of the rotatable seed disk from the air pressure source so that the seed is released from the apertures. The seed then follows a trajectory away from the disk into a seed tube or the like towards the ground.  
         [0003]     Air pressure seed meters commonly utilize plastic seed disks which vary in configuration depending on the type and size of seeds being metered. For example, a vacuum meter may use either a celled seed disk or a flat seed disk installed at a given location on a driven hub. The seed trajectory off the disk in the release area typically varies with the type of seed disk being used. The trajectory off the celled disk tends to be more centered relative to the seed tube entry walls than the trajectory for the flat disk, which is closer to the proximate seed tube wall. If the trajectory for the celled disk is optimized, the seed drop will not be in the optimum location for the flat disk. As a result, the seeds released from the flat disk will be offset more from center and will tend to bounce off of the proximate wall instead of falling towards the desired location within the seed tube. The seed bounce off the proximate wall produces unwanted seed spacing variations. In commonly assigned and copending application Ser. No. ______ Flat Type Seed Meter Disk with Axially Offset Surface, a flat disk is described wherein apertures are spaced along a circumferential rim offset axially from the remainder of the disk to approximately duplicate the seed release location and characteristics of a cell type seed disk.  
       SUMMARY OF THE INVENTION  
       [0004]     It is therefore an object of the present invention to provide an improved seed disk which overcomes the aforementioned problems. It is another object to provide such a seed disk for improved seed trajectory to reduce or eliminate unwanted seed bounce as the seed moves from the seed release point towards the ground.  
         [0005]     It is a further object of the present invention to provide a seed disk configuration that provides generally identical seed trajectories for both a flat seed disk and a celled disk so that the meter can be placed in the same position for both seed disks.  
         [0006]     A flat disk type circular seed disk is provided with circumferentially arranged seed attracting apertures. The apertures are located on a series of individual protrusions offset axially from the remainder of the disk and generally duplicate the seed release location and characteristics of a cell type seed disk. The offset allows the seed to fall in the correct location of the seed tube to reduce or eliminate unwanted seed bounce and provide better seed delivery to the ground and better seed spacing as compared to flat disks without the offset. In one embodiment of the invention, the protrusions have forward apertured walls facing the direction of rotation of the disk for aggressive stirring and seed pick up. In another embodiment, the protrusion forward walls are angled to have a substantial radial component for less aggressive stirring and different seed release characteristics. In a third embodiment, the apertures open in a radial direction, and a ledge member stirs and accelerates seeds and provides rear support for captured seeds.  
         [0007]     These and other objects, features and advantages of the present invention will become apparent from the following description in view of the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of a flat type seed meter disk typical of the prior art.  
         [0009]      FIG. 2 a  view partially in cross sectional showing a typical trajectory for the prior art seed disk of  FIG. 1 .  
         [0010]      FIG. 3  is a perspective view of a flat type seed meter disk having protrusions providing axial offset for improved seed trajectory.  
         [0011]      FIG. 4  is a perspective view of the rear side of the disk of  FIG. 3 .  
         [0012]      FIG. 5  is an enlarged perspective view of an outer circumferential portion of the seed disk of  FIG. 3   
         [0013]      FIG. 6  is a view similar to  FIG. 5  but showing an alternate embodiment with protrusions having angled faces.  
         [0014]      FIG. 7 a  view of another embodiment of the seed disk having protrusions with radial apertures and with ledges facing generally in the direction of rotation adjacent the apertures.  
         [0015]      FIG. 8  is a perspective view of the seed meter with parts removed to show the double eliminator and brush retainers for the disk of  FIG. 3 .  
         [0016]      FIG. 9  is a view similar to  FIG. 2  illustrating the improved trajectory of the seed disk with protrusions.  
         [0017]      FIG. 10  is a view of a portion of a seed disk having protrusions with axially directed seed retention areas. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Referring to  FIGS. 1 and 2 , a seed meter  10  in communication with a seed hopper  12  includes a housing  14  rotatably supporting a seed disk  20 . The housing  14  as shown has a vacuum side  16  and a seed receiving side  18  which are hinged together and secured in a closed position by a conventional latching arrangement (see  21  of  FIG. 8 ). The rotatable seed disk  20  includes a hub portion  21  secured to a drive coupling  22  ( FIG. 8 ).  
         [0019]     The seed disk  20 , which is shown as a conventional flat sweet corn disk in  FIGS. 1 and 2 , includes a series of apertures  24  uniformly spaced radially inwardly of a serrated cleanout and stirring edge  26  and passing from the seed side of the disk  20  through to the vacuum side of the disk. Seed accelerating and stirring structure  27  extends radially inwardly from the apertures  24  on the seed side of the disk. As the periphery of the disk  20  passes through a supply or puddle of seed in the seed receiving side  18  of the housing  14 , the vacuum communicated through the apertures  24  draws and holds seed against the apertures. The edge  26  and the structure  27  stir and accelerate the seed adjacent the disk to facilitate capture of the seed by the apertures  24 .  
         [0020]     The seed receiving side  18  communicates with a supply of seed in the hopper  12 . An outlet  28  connects the interior of the seed meter  10  to a seed tube  29  or other delivery device for directing the seed to the ground. The vacuum side  16  of the seed meter  10  is provided with a seal  30  which defines a seed a seed release zone  34  where the vacuum is isolated from the apertures  24  to release the seeds held on the apertures of the disk  20 . The vacuum side  16  is coupled to a vacuum source (not shown). Although the present invention is being described as being used on a vacuum or negative air pressure seed meter it could also be used on a positive air pressure seed meter.  
         [0021]     Seed deposited in the hopper  12  flows downwardly from the hopper  12  through an inlet into the seed receiving side  18  of the housing  14 . The seed forms a puddle at the bottom of the housing defined by the seed disk  20  and the seed receiving side  18 . Brush retainers  40  ( FIG. 8 ) form a barrier in the housing  14  that prevents seeds in the seed puddle from directly entering the outlet  28 . A vacuum is applied to a seed trapping zone on the vacuum side  16  which draws air from the seed receiving side  18  through apertures  24 . This flow of air attracts seeds to the apertures and holds the seeds on the apertures. Further rotation takes the seed out of the area defined by the seed trapping zone to the seed release zone defined by seal  30 . No vacuum exists in the seed release zone so the seed is released from the seed disk and falls into outlet  28 . From the outlet  28 , the seed is directed through the seed tube  29  to the planting furrow. A doubles eliminator  48  is connected to the housing on the seed side of the disk to eliminate any incidences of multiple seeds in an aperture.  
         [0022]     As can be seen in  FIG. 2 , a seed trajectory  50  extends downwardly from a seed release point  52 . The trajectory  50  of the seed tends to brush an uppermost portion of a proximate wall  54  at the outlet  28  causing the falling seeds to bounce towards a distal wall  56 . Additional seed bounce initiated as a result of the seeds hitting the wall close to the uppermost portion of the outlet causes unpredictable irregularity in seed spacing in the furrow.  
         [0023]     Referring now to  FIGS. 3-5 , therein is shown an improved seed corn disk  60  having a central connection hub  61  and an outer circumferential portion  62 . A plurality of apertures  64  are spaced uniformly about the circumferential portion  62  and extend from seed side  65  through to the opposite side  66  of the disk  60 . The disk  60  rotates in a forward direction R generally in a rotational plane  60   p  about an axis  60   a.    
         [0024]     The outer circumferential portion  62  includes a plurality of dome-shaped members or protrusions  80  raised relative to a generally planar central portion  68 . As shown in  FIGS. 3 and 5 , the protrusions  80  include seed retention walls  82  facing the direction of rotation R and opening at  84  to the corresponding apertures  64  adjacent U-shaped shoulders  86  in the walls. Trailing walls  88  of arc-shaped configuration extend upwardly from the surface of the portion  68  to a flat protrusion top portion  90 . Seed stirring and accelerating structure  69  is located radially outwardly of the protrusions  80 . The protrusions  80  also stir and accelerate the seed to facilitate capture and eliminate need for accelerating and stirring structure radially inwardly of the seed retention areas.  
         [0025]     The configuration of the protrusions  80  shown in  FIGS. 3 and 5  provides aggressive scooping of seed from the seed puddle. The protrusion face  82  is perpendicular to the tangent of the diameter of the disk which enhances seed scooping. Differential pressure communicated via openings  84  and apertures  64  captures and holds seed at the shoulder  86  against the seed retention walls  82 . When the differential pressure is cut off, the seed is released from the walls  82  to follow the trajectory shown in  FIG. 9 . The offset provided by the protrusions  80  causes release point  76  of each captured seed to extend axially in the direction of the seed side  65  of the disk so that the seed falls more centrally relative to the outlet  28  along a trajectory  89  offset inwardly from the proximate wall  54 , compared to the trajectory  50  for the prior art disk  20  of  FIG. 2 . The curved trailing walls  88  help eliminate trajectory-altering interference between released seed and an adjacent protrusion  80 . The new trajectory  89  reduces unwanted seed bounce and results in more uniform seed spacing in the furrow.  
         [0026]     Referring to  FIG. 6  protrusions  180 , which are similar in construction to the protrusions  80  described above, include protrusion faces or seed retaining walls  182  angled radially outwardly with respect to the direction of rotation R. As shown, the faces  182  form an acute angle of approximately  45  degrees with respect to a radial line extending from the center of the disk  160  through the protrusion  180 . The walls  182  open at  184  to the corresponding apertures  64  adjacent U-shaped shoulders  186  in the walls. Trailing walls  188  include angled wall portions  189  extending. rearwardly and radially inwardly from the faces  182  and are curved at the aft portion. The walls  182  and  188  extend upwardly from the surface of the portion  68  to a flat protrusion top portion  190 . The configuration of the protrusion  180  with the angled face  182  facilitates seed release at the three o&#39;clock position without hitting the preceding protrusion  190 .  
         [0027]     Referring to  FIG. 7 , another embodiment is shown on disk  260 . The general configuration of the disk  260  is similar to that described for  FIGS. 5 and 6  above, but protrusions  280  include radially facing seed capturing walls  282  opening radially outwardly at  284  with little or no angular component facing in the direction of rotation R. To provide seed support, seed scooping and acceleration, a trailing ledge or radial extension  285  is offset behind the seed capturing opening  284 . The radially facing seed capturing walls  282  eliminate interference between a released seed and the preceding protrusion  280 .  
         [0028]     Another embodiment is shown on a portion of a disk  360  in  FIG. 10 . Protrusions  380  have walls  382  defining a truncated cone shape wherein the apertures  64  open at  384  in the axial direction. Air pressure communicated through the apertures hold seeds on circular ledge areas  386 . At the release position, the pressure is cut off, and the seeds fall in a trajectory offset from the adjacent planar portion of the disk  360 .  
         [0029]     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.  
       Assignment  
       [0030]     The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere &amp; Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere &amp; Company or otherwise.