Abstract:
A vacuum seed planter uses a single seed plate for planting multiple plots of seeds. The seed plate rotates through a seed chamber and uses vacuum pressure to pick up seeds to be planted, the seed chamber having an inlet passage for receiving seeds. A singulator dislodges excess seeds from the seed plate, and the excess seeds fall into an excess-seed compartment adjacent the seed chamber, the compartment having an outlet passage for evacuation of the excess seeds. A valve is movable between an operating position, in which the inlet passage communicates with a supply of seed and the outlet passage communicates with a vacuum source for evacuating excess seeds, and an evacuation position, in which the vacuum source is in communication with the inlet passage for evacuating the seeds in the seed chamber. Vacuum pressure on the seed plate can be maintained during evacuation of the seed chamber and excess-seed compartment.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Benefit is herein claimed of the filing date under 35 USC §119 and/or §120 and CFR 1.78 to U.S. Provisional Patent Application Serial No. 60/250,099, filed on Nov. 30, 2000, entitled “Vacuum Seed Planter for Test Plots.” 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates in general to a seed planter, and in particular to an improved vacuum seed planter for test plots. 
     2. Description of the Prior Art 
     Vacuum seed planters are used to meter the amount of seeds being planted, providing for proper spacing of seeds and reducing seed waste. The vacuum planters typically have a seed plate with radially-spaced apertures and a vacuum source for creating a vacuum pressure in the apertures. The seed plate passes through a seed chamber containing seeds to be planted, individual seeds being drawn to the apertures. A singulator device removes excess seeds, preferably leaving one seed per aperture, the excess seeds falling back within the seed chamber. When changing seed types, the seed chamber is emptied through a door near the bottom of the chamber. An example of a typical vacuum planter is the Monosem NG Plus, available from A.T.I., Inc., of Lenexa, Kans. 
     It is also known in the art to evacuate the seed chamber using a vacuum source. One example uses a valve for redirecting the vacuum from the seed plate to the seed chamber for evacuating the chamber. In this apparatus, the seed chamber cannot be emptied while the seed plate is in use, since the vacuum pressure is switched from the seed plate to the evacuation tube. 
     It is desirable to plant multiple plots of seeds, each plot having a different seed type. However, the prior art planters require that the change of seed type occur in an alleyway or require two seed plates, each having a different type of seed. In the two-seed-plate device, the first plate is used to plant a plot, then the second plate is used while the seed for the first plate is changed. The extra seed plate adds additional cost, weight, and complexity to the standard seed planter. 
     Therefore, there is a need for a seed planter having a single seed plate and that is capable of quickly and easily planting multiple seed plots. Also, there is a need for a seed planter that ensures that seeds can be removed from the rotating seed plate between rows or when changing seed types. 
     SUMMARY OF THE INVENTION 
     A vacuum seed planter uses a single seed plate for planting multiple plots of seeds. The seed plate rotates through a seed chamber and uses vacuum pressure to pick up seeds to be planted, the seed chamber having an inlet passage for receiving seeds. A singulator dislodges excess seeds from the seed plate, and the excess seeds fall into an excess-seed compartment adjacent the seed chamber, the compartment having an outlet passage for evacuation of the excess seeds. A valve is movable between an operating position, in which the inlet passage communicates with a supply of seed and the outlet passage communicates with a vacuum source for evacuating excess seeds, and an evacuation position, in which the vacuum source is in communication with the inlet passage for evacuating the seeds in the seed chamber. Vacuum pressure on the seed plate can be maintained during evacuation of the seed chamber and excess-seed compartment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed to be characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a side view of the base unit of a seed planter constructed in accordance with the present invention and shown with outer portions of the seed planter removed. 
     FIG. 2 is a side view of the seed planter of FIG. 1 showing a seed plate and a singulation device mounted to the base unit. 
     FIG. 3 is a side view of the seed planter of FIG. 2 showing a seed chamber and a slide mechanism mounted thereto. 
     FIG. 4 is a side view of the seed planter of FIG. 3 showing a cover mounted thereto. 
     FIG. 5 is a reverse side view of the cover, seed chamber, and slide mechanism of FIGS. 3 and 4. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 through 5 show a seed planter  11  constructed in accordance with the present invention. Beginning with a base unit  13  shown in FIG. 1, the various components of seed planter  11  are sequentially added through FIG.  4 . FIG. 5 illustrates a reverse or opposite side view of an outer portion of seed planter  11 . As shown in FIG. 1, the generally circular base unit  13  of seed planter  11  has a stationary, substantially planar UHMW plastic wear ring  15  having a pair of flat, arcuate-shaped surfaces  17 ,  19 . An annular slot or plenum  21  is located between surfaces  17 ,  19  for drawing a vacuum therethrough from a tube  23  located on a backside of base unit  13 . Wear ring  15  and, thus, surfaces  17 ,  19  and plenum  21 , extend in a circular path about a rotatable drive member  25  for approximately 280 degrees (e.g., from about a “7:30” position, to a “4:30” position). As measured from the center of drive member  25  to a center of plenum  21 , plenum  21  has a uniform radius  27 . Drive member  25  may be driven by the planter transmission, a hydraulic drive, or other means. 
     Referring now to FIG. 2, a seed plate  31  and a singulation device  33  are shown mounted to base unit  13  of seed planter  11 . Seed plate  31  is preferably formed from stainless steel, and is rotatably mounted to drive member  25  relative to stationary base unit  13  and wear ring  15 . Seed plate  31  has an outer surface  34  and a plurality of symmetrically spaced-apart through holes  35 . Seed plate  31  is mounted against wear ring  15  (FIG. 1) such that seed plate  31 &#39;s backside surface (not shown) lies substantially flush against surfaces  17 ,  19 . The center of each hole  35  is spaced apart from the center of seed plate  31  by a uniform radius  37  that is essentially equal to radius  27  of plenum  21  so that a consistent vacuum is drawn through each hole  35 . Seed plate  31  maybe provided with a greater or lesser number of holes  35  with a larger or smaller diameter depending on a variety of factors, including the size of the seeds to be planted. Seed plate  31  also has a smaller diameter intermediate plate  41  that is concentrically bolted to the center thereof for rotation therewith. Intermediate plate  41  is preferably formed from brass, and has a plurality of small, symmetrically spaced-apart agitators  43  that extend radially outward therefrom. Agitators  43  stir the seeds and facilitate greater accuracy in seed planter  11 . 
     Singulation device  33  is stationarily mounted to base unit  13  of seed planter  11  and, thus, does not rotate with seed plate  31 . Singulation device  33  is provided with a substantially planar row of progressive teeth  45  that are located adjacent to outer surface  34  of seed plate  31  in an essentially parallel configuration. The smallest tooth  47  on the lower left of singulation device  33  extends immediately adjacent to holes  35  as they rotate, while the largest tooth  49  on the upper right is designed to cover one-half to three-fourths of the surface area of holes  35 . If more than one seed is drawn to a single hole  35 , teeth  45  of singulation device  33  progressively “knock off” the extra seeds until one is left on each hole  35 . In addition, the singulation device  33  may be adjusted to be more or less aggressive in knocking off the extra seeds. 
     In FIG. 3, a seed chamber  51  and a schematic view of a slide mechanism  53  have been added to the sub-assembly of seed planter  11  depicted in FIG.  2 . Seed chamber  51  mounts to base unit  13  adjacent to and outside of singulation device  33 . Seed chamber  51  has an interior reservoir (not shown) for holding and queuing seeds dropped down through an inlet tube  55  that extends from a hopper (not shown). Seed plate  31  rotates through the reservoir such that one or more seeds are drawn to each hole  35  and lifted toward singulation device  33 . Teeth  45  then reduce the seed count per hole  35  to one. When the extra seeds are knocked off holes  35 , they fall down into a compartment  57  (shown in section) that is separate from the reservoir in seed chamber  51 . The extra or “rejected” seeds in compartment  57  are evacuated through an outlet tube  59  that extends upward to another hopper (not shown). 
     Slide mechanism  53  is shown in schematic in FIG. 3 for ease of understanding, and more realistically in FIGS. 4 and 5. Slide mechanism  53  is provided for selectively controlling the flow of seeds through inlet tube  55  and outlet tube  59 . Slide mechanism  53  comprises a base  61 , preferably formed from nylon, a block  63  that is slidably moved on base  61  by a solenoid  65  or air cylinder with a linear bearing, and an outer protective plate  67  (FIGS.  4  and  5 ). As shown in FIG. 4, a small alley wiper  68  is also located adjacent to seed plate  31  at approximately the “12:00” position (rotationally beyond singulation device  33 ). Alley wiper  68  may be powered by any suitable device (not shown), such as an electric solenoid or air cylinder. After one plot of planting is complete, alley wiper  68  is deployed to wipe off any remaining seed on seed plate  31  to make sure that no seeds are carried over to the next plot, and to insure that no seeds are planted in the alleyway therebetween. When a particular plot is being planted, alley wiper  68  is retracted out of the way so seed can be planted. 
     Referring now to FIGS. 3 and 5, block  63  has a pair of vertical through holes  69 ,  71  that simultaneously axially align with tubes  55 ,  59 , and holes  70 ,  72  in base  61 , respectively, during normal operation. Thus, seed typically falls through hole  69  and inlet tube  55  on its way to seed chamber  51 , and the extra seed knocked off by singulation device  33  and/or alley wiper  68  is evacuated through outlet tube  59  and hole  71 . However, when solenoid  65  is actuated, block  63  is moved away therefrom (to the left in FIG. 3, and to the right in FIG. 5) such that hole  71  is axially aligned with inlet tube  55 . In this alternate position, seed chamber  51  is evacuated, and the lower end of hole  69  and outlet tube  59  are blocked. While seed chamber  51  is being evacuated, new seed can be released into hole  69 . Since the lower end of hole  69  is sealed by base  61 , the new seed stages there until block  63  returns to its starting position. At that time the new seed falls through hole  70  in base  61  and into seed chamber  51 . FIGS. 4 and 5 also illustrate an outer protective cover  75  for seed planter  11 . Cover  75  has an opening  77  near its lower end, and an optional trap door located opposite opening  77 . Optimal trap door is blocked by seed chamber  51 . 
     In operation, seed planter  11  is used to plant one seed at a time at very accurate intervals. Seeds are dispensed from a hopper through inlet tube  55  into the reservoir in seed chamber  51 . As seed plate  31  rotates and a vacuum is drawn through plenum  21  and holes  35 , one or more seeds are attracted to each hole  35  at about the “7:30” rotational position. Agitators  43  on intermediate plate  41  stir the seeds and facilitate greater accuracy in seed planter  11 . The seeds on holes  35  are rotated toward singulation device  33  where they are progressively reduced to a single seed per hole  35  by teeth  45 . From the “12:00” position clockwise to the “4:30” position a single seed is drawn to each hole  35  and remains there since alley wiper  68  (FIG. 4) is retracted in normal operation. At approximately the 4:30 position, plenum  21  ends (FIG. 1) and the seeds sequentially drop off of plate  31  and through opening  77  to the ground where they are planted at a desired rate. The extra seeds fall into compartment  57  where they are evacuated through outlet tube  59 . 
     After the plot of planting is complete, alley wiper  68  is deployed to wipe off any remaining seed on seed plate  31  to make sure that no seeds are carried over to the next plot, and to insure that no seeds are planted in the alleyway therebetween. Solenoid  65  is actuated to move block  63  and hole  71  and evacuate the reservoir in seed chamber  51 , at which time new seed is released into hole  69 . When block  63  returns to its original position, the new seed falls into seed chamber  51 . 
     Alternatively, multiple, sequential plots of seeds can be planted without deploying alley wiper  68  to remove from seed plate  31  the remaining seed from the initial plot. At a desired location, solenoid  65  is actuated to move block  63 , the reservoir in seed chamber  51  being evacuated while the captured seeds from the initial plot rotate with seed plate  31 . A sufficient time is allowed for evacuation of seed chamber  51 , then block  63  is returned to its original position, allowing seed for the subsequent plot to fall into seed chamber  51 . These new seeds are drawn to holes  35  on seed plate  31  at positions rotationally rearward from the seeds of the initial plot. Typically, the subsequent-plot seeds are separated from the initial-plot seeds by several vacant holes  35  on seed plate  31 , the number of vacant holes being determined by the length of time before new seed is released into seed chamber  51  and the rate of rotation of seed plate  31 . As seed plate  31  rotates, the seeds of the initial plot reach the position of the end of plenum  21  and drop, then seeds from the subsequent plot reach the end of plenum  21  and drop. This process may take approximately 1.5 seconds, and may be repeated for multiple subsequent plots, allowing a large number of plots per row. 
     Several advantages are realized from using the present invention. Multiple plots of seeds can be planted with a single seed plate and can be planted quickly without requiring that the change of seed type occur in an alleyway. Seeds can be changed while the original group of seeds is still being planted, reducing the total time for planting. Also, the seed planter of the invention ensures that seeds can be removed from the rotating seed plate when desired by using the alley wiper. 
     While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.