Seed distribution system and method for a seeding implement

A seed distribution system includes an upright main hopper for containing a mass of seeds. The input end of a seed tube projects into the lower portion of the hopper near the bottom of the seed mass. The input end of the seed tube is located within the output end of an air supply tube and terminates inwardly of the supply tube. The seeds in the main hopper are pneumatically captured by creating a generally dome-shaped area in the seeds adjacent the input end and sweeping seeds from the area into the input end. The captured seeds are propelled through the seed tube to a secondary hopper adjacent a seed metering device. To provide automatic level control, the delivery end of the seed tube is supported within the secondary hopper so that, as the seed level rises in the hopper, air flow and thus seed delivery rate will decrease. Automatic seed distribution from the bottom of the central hopper to the secondary hopper is accomplished simply and reliably with no moving parts other than those associated with the source of air.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a seeding implement and more 
specifically to a seed distribution system for a planter or grain drill or 
the like. 
2. Related Art 
Seeders and planters which have individual metering devices with 
corresponding hoppers located across the width of the implement require 
individual filling of each hopper which can be quite time consuming and 
inconvenient. In the past, implements with a single material storage area 
often had metering systems located a substantial distance from the furrow 
opener, and seed placement with such implements was less precise than 
those that have metering devices near the opener. Although various types 
of air systems exist for supplying individual row meters from a central 
hopper, heretofore there has not been a reliable and yet simple and 
inexpensive single point fill structure for use with individual meters. 
Most central hopper implements are relatively complex and include a number 
of moving parts. 
BRIEF SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
seed distribution system for a planting implement. It is another object to 
provide such a system wherein seed from a central hopper is distributed to 
a plurality of secondary or mini-hoppers located adjacent seed meters. 
It is a further object of the present invention to provide an improved seed 
distribution system having a minimal number of moving parts. It is a 
further object to provide such a system which is relatively inexpensive 
and yet highly reliable. It is still another object to provide such a 
system which includes a main storage hopper that feeds a plurality of 
mini-hoppers, wherein automatic level control in the mini-hoppers is 
achieved without moving parts. 
It is yet another object of the present invention to provide an improved 
seed distribution system for pneumatically conveying seeds from the bottom 
of a mass of seeds in a hopper to locations adjacent planter or drill row 
units. It is a further object to provide such a system which requires no 
moving parts other than a fan and wherein the seed delivery rate is easily 
adjustable. 
A seed distribution system constructed in accordance with the teachings of 
the present invention includes an upright main hopper for containing a 
mass of seeds. The input end of a seed tube projects into the lower 
portion of the hopper near the bottom of the seed mass. A source of air 
pressure is communicated to the hopper in the area of the seeds around the 
input end to pneumatically capture seeds in the seed tube and propel the 
captured seeds through the tube to a secondary hopper adjacent a seed 
metering device. To provide automatic level control, the delivery end of 
the seed tube is supported within the secondary hopper to provide a 
self-throttling effect so that, as the seed level rises in the hopper, air 
flow and thus seed delivery rate will decrease. 
The seeds in the main hopper are pneumatically captured by creating a 
generally dome-shaped area of seeds and air adjacent the input end of the 
seed tube and propelling seeds from the area into the input end. The air 
outlet for creating the dome-shaped area directs air in a first direction 
into the seed mass adjacent the input end of the seed tube and exhausts 
the air in a second direction substantially different from the first 
direction. Preferably, the input end of the seed tube is located within 
the output end of the air supply tube and terminates inwardly of the 
supply tube. The tube spacing is small to prevent seeds from moving into 
the area between the tubes. 
Automatic seed distribution from the bottom of the central hopper to the 
secondary hoppers is accomplished simply and reliably with no moving parts 
other than those associated with the source of air. Seed delivery rate 
through the seed tubes can be adjusted by changing the location of the 
input end of the seed tube relative to the output end of the air supply 
tube and by changing the angle of the tubes in the mass of seeds. A 
clean-out door located in the bottom of the central hopper adjacent the 
tubes facilitates servicing and adjustment of the unit. 
These and other objects, features and advantages of the present invention 
will become apparent to one skilled in the art upon reading the following 
detailed description in view of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to FIG. 1, therein is shown a portion of a grain drill or 
similar seeding implement 10 having a transversely extending main frame. A 
plurality of planter row units 14 are spaced across the width of the frame 
for depositing seed in the ground in parallel rows. 
A main or central seed hopper 20 is supported on the frame, and a seed 
distribution system indicated generally at 32 supplies seed from the 
hopper 20 to individual secondary or mini-hoppers 34 on each of the row 
units 14. A seed meter 38 meters seed from the mini-hopper 34 to a 
conventional seed boot assembly for deposit in a furrow formed by the 
opener device on the row unit 14. 
The central seed hopper 20 includes an upright, transversely extending seed 
storage area 40 for containing a mass of seeds and facilitating delivery 
of the seeds from a bottom location 41 into the seed distribution system 
32. The hopper 20 includes upright front and rear walls 42 and 44 with 
lower inwardly converging bottom portions 46 and 48 for channeling seed to 
the location 41. A lowermost cleanout door 50 is hinged at 52 to 
selectively close and provide access to the location 41 and the input area 
of the distribution system 32. The sides of the hopper 20 are closed by 
end walls 56. A top 60 with inlet door 62 closes the upper portion of the 
hopper 20. When the doors 50 and 62 are closed, the hopper 20 is sealed so 
that the storage area 40 can be pressurized during operation. 
As best seen in FIG. 2, the bottom portion 48 which extends inwardly from 
the rear wall 44 terminates at a central location above the opposite 
bottom portion 46. An air gallery or manifold 70 extends substantially the 
width of the hopper 20 and includes a forward wall 72 which projects 
downwardly from the lower end of, and is perpendicular to, the bottom 
portion 48. The manifold 70 also includes a rear wall 74 extending 
parallel to the wall 72. A bottom wall 76 closes the lower portion of the 
manifold 70, and the bottom portion 48 defines the upper boundary of the 
manifold which has a generally rectangular cross section as shown. End 
walls 78 close the sides of the manifold, with an air inlet 80 located in 
one of the walls 78. An air supply line 84 attached to the inlet 80 is 
connected to the output of a constant pressure fan 86 to supply air to the 
manifold 70. 
A plurality of air supply outlets 90 are supported in transversely spaced 
relationship along the length of the manifold forward wall 72. The outlets 
90 are straight lengths of conduit with circular cross sections and end 
portions 92 which project into the lower portion of the mass of seeds 
within the hopper 20. The inner ends of the outlets 90 terminate along the 
inner surface of the forward manifold wall 72. Preferably, there is an 
individual outlet 90 associated with each of row units 14. 
A seed tube 100 of circular cross section with diameter less than the inner 
diameter of the outlet 90 projects through the rear wall 74 of the 
manifold 70 and into the outlet, at an angle of greater than approximately 
twenty to twenty-five degrees from the horizontal. The inlet end 102 of 
the seed tube 100 is located inwardly from the end portion 92 of the 
corresponding outlet 90 with the distance (d) between the ends 102 and 92 
being adjustable within a range of approximately one-half to three inches 
to also affect seed delivery rate. The seed tube 100 is slidably received 
in the rear wall 74 of the manifold 70 so that the distance d can be 
adjusted by moving the tube in the fore-and-aft direction. The seed tube 
100 projects rearwardly and upwardly from the rear wall 74 of the manifold 
70 and extends to an output end 106 (FIG. 1) located within the 
corresponding mini-hopper 34 to provide a self-throttling arrangement 
described in detail below. 
Air blown into the air manifold 70 is directed through the outlets 90 
between the inner surface of each outlet 90 and the outer surface of the 
end of the corresponding seed tube 100 associated with that outlet. The 
air creates a positive pressure near the outlet 90. A dome-shaped area of 
air and seeds or pocket 110 (see FIG. 2) is formed in the seed mass at the 
end 92 of the outlet 90. The air passing through the dome-shaped area 110 
is exhausted through the seed tube 100, in a direction directly opposite 
the direction of input of the air (i.e., a change of direction of the air 
of approximately 180 degrees). The moving air sweeps seeds from the area 
110 into the inlet end 102 of the seed tube 100. The seeds which are swept 
into the tube 100 are propelled to the output end 106 by the air exhausted 
from the pocket 110. The angle (.alpha.) of the seed tube 100 with respect 
to the horizontal and the recessing of the seed tube end 102 within the 
outlet 90 help prevent seed build-up within the tubes that would cause 
slugging or inability to commence seed delivery on start up of the fan. 
The angle (.alpha.) of the seed tube 100 in the seed mass is preferably 
about thirty-five degrees with respect to the horizontal, although the 
angle can be adjusted to affect seed delivery rate and to optimize 
performance for different tube sizes. A steeper angle decreases seed 
delivery rate while a shallower angle increases rate. Below about twenty 
to twenty-five degrees, the seed tube 100 will slug with grain and become 
ineffective for delivering seed to the mini-hopper 34. Decreasing the 
distance d between the ends 92 and 102 increases delivery rate while 
increasing the distance d slows delivery. For the tube sizes given below: 
above approximately three inches of separation seed delivery stops 
completely; below about one-half inch of separation, the seed tube 100 
slugs. 
In addition to seed tube angle and tube end separation adjustments, conduit 
size and fan pressure can be changed to vary the seed delivery rate. Also, 
changing the height of the seed delivery tube 100 will affect seed 
delivery rate. 
The separation between the outer wall of the seed tube end 102 and the 
inner wall of the outlet 90 is preferably kept small relative to the size 
of the seed so that the seed will not work back between the tubes and into 
the manifold 70 during transport. Using tubes with inner diameters of 1.0 
inch and 1.59 inch for the seed tube 100 and the outlet 90, respectively, 
provides approximately equal air inlet and outlet areas and prevents corn, 
soybean and similar sized seeds from working into the manifold. 
Each mini-hopper 34 has sidewalls 134 and a converging bottom portion 136 
opening into the meter 38. The output end 106 of the seed tube 100 extends 
through the upper portion of the sidewall 134 and is supported within the 
hopper with the output end adjacent the sidewall and directed downwardly 
toward the bottom portion 136. As seed is delivered through the tube 100 
and builds up within the hopper toward the end 106, a restriction to air 
movement through the end builds. As the seed reaches a preselected level 
in the hopper 34, the end 106 becomes restricted (see FIG. 1) to the point 
seed can no longer be propelled through the tube and seed delivery stops. 
As the seed is dispensed by the meter 38 and the level drops in the hopper 
34 so that the restriction is removed, air flow increases sufficiently so 
that seed delivery is again commenced. Seed delivery to the hopper 34 then 
continues until the seed again reaches the preselected level. 
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.