LeeBoy 8520C - Pavement Crown Adjustment; Setting the Crown Procedure

4-36 LeeBoy 8520C Conveyor Paver
Operation
Setting the CrownSetting the Crown
The screed can also be set to control the pavement
valley, or crown. A pavement crown is the elevation of
the middle in relation to the edges, and insures proper
drainage of the pavement.
NOTE: Maximum crown is two inches.
To adjust the crown:
1. Loosen the lock-down bolts in slotted bars before
adjusting crown and valley mechanism. (Figure
4-77)
Figure 4-77. Loosen Lock-Down Bolts
2. Use the crown handle adjuster for setting positive or
negative crown: (Figure 4-78)
Gauge
Crown
Handle
Adjuster
Figure 4-78. 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 4-79)
• Negative crown is the lower in the center of
the screed plate, often used in an alley where
drainage is necessary. (Figure 4-79)
Figure 4-79. 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.