Great Plains 800 Operator Manual - Manual (Page 32)

28 800 Table of Contents Index Great Plains Manufacturing, Inc.
175-057M Table of Contents Index 2011-10-25
Opener Frame Down-Force
To properly adjust seeding depth, you need an
understanding of how the opener frame, opener springs,
discs and press wheels work. The opener frame
adjustment affects all rows at once.
Refer to Figure 18 and Figure 19
The openers are mounted on a pivoting tube
.
A hydraulic cylinder mounted on a floating lug controls
the openers. Springs on the opener bodies provide down
pressure for the opener discs to cut a seed furrow.
A pivot-stop pin
is placed in one of five sets (A…E) of
holes to limit the rotation of the floating lug and
thereby controls spring length and down pressure on all
openers.
Changing the position of the pivot-stop pin changes
opener down-pressure across the drill. You can also
change the spring length (page 30) or mounting height of
individual openers (page 30), such as in tire tracks.
Press wheels (page 33) are mounted on the opener
bodies behind the opener discs, and perform two
functions:
• They close the furrow and firm the seed bed. To
provide consistent seed firming, the press wheels are
free to move down from their normal operating
position. This maintains pressing action even if the
opener arm lifts at obstructions.
• The press wheels control opener depth. The higher
the press wheels run, the deeper seed is placed.
Spring Down Pressure–All Openers
The amount of down pressure needed for the opener
discs to penetrate the soil varies with field conditions.
The objective in selecting a pivot-stop pin hole, and a
press wheel height, is to achieve the desired planting
depth while keeping the drill frame and the row unit
frames level with the ground.
Note: The setting of the pivot-stop pin interacts with the
setting of the press wheel height. When adjusting
one, recheck the other.
To increase or decrease all-rows spring down pressure:
1. Raise the drill (to free the pin).
2. Move the pivot-stop pin .
The holes in the floating lug are lettered:
A provides the greatest down pressure and
E provides the least.
As the pin is moved to hole for transport, keep records
of what hole is optimal for fields and conditions worked.
Note: To maintain consistent opener down pressure, fully
extend the hydraulic cylinder each time you lower
the openers.
Figure 18
Down-Pressure Decal
818-827C
1
3
Pivot
Point
4
1
2
3
Figure 19
Adjusting Down-Pressure
28282
1
2
3
2
2
3
4