LeeBoy 6150 - Mat Texture Adjustment

4
LeeBoy 6150 Conveyor Paver 4-31
Operation
Figure 4-66. Crown Settings
1 - Positive (+)
2 - Zero (0)
3 - Negative (-)
NOTE: Crown may be placed in the leading edge and/
or the trailing edge of the screed plate. Crown
in the leading edge aids material ow under
the screed plate only. Trailing edge crown
puts a crown in the mat.
Example: The trailing edge crown is 0 and the
leading edge crown is 1/8 inch. There will not be
any crown in the mat, but the material ow under the
screed plate will be improved.
Mat Texture Adjustment
The Angle-of-Attack (AOA) is the angle made by the
screed plate in relation to the grade being paved.
Factors that determine the AOA include mat depth,
screed weight, material stability and screed bottom
plate depth (front to back).
A screed should run with 1/8- to 1/4-inch nose-up
AOA so the full width of the screed bottom is utilized
to produce the best mat texture. Running the screed
at extremes of increased or decreased AOA results
in poor mat texture as only a small portion of the
screed bottom plate is being used for compaction, and
decreases the life of the screed plate.
When the head of the material is maintained at a
consistent half-auger level and uniform across the width
of the screed, the forces acting against the screed are
constant, the AOA remains unchanged, and the texture
of the material on the mat is uniform. (The augers also
operate more efciently if the material level remains at
half-auger.)
2. Use the crown handle adjuster for setting positive or
negative crown: (Figure 4-65)
Gauge
Crown
Handle
Adjuster
Figure 4-65. Crown Adjustment
• For increased positive crown push down on
adjuster.
• For increased negative crown pull up on
adjuster.
3. Use the gauge at the center of the screed above the
standing platform. If the needle is above the zero,
you will have positive crown. If the needle is below
the zero, you will have negative crown.
4. To get exact crown or valley, measure the distance
between a at level surface to the center bottom
portion of screed. Make adjustments with crown and
valley control.
• Positive crown is when the middle of the mat
is raised to permit water to drain to each side.
(Figure 4-66)
• Negative crown is the lower in the center of
the screed plate, often used in an alley where
drainage is necessary. (Figure 4-66)