MAT CROWN ADJUSTMENT
The flat screed bottom can be flexed as its center
area to produce a finished mat having a positive or
negative crown for water drainage. (See Figure 10)
For 10 ft. wide paving the maximum positive crown is
2". The maximum negative crown is 3/4".
Screed Bottom with Crowning Arms
Figure 10
Crown adjustment is accomplished by means of
four crowning arms which are located on top of the
screed but are bolted to the screed bottom. A turn
buckle adjustment joining each pair of crowning arms
permits screed bottom flexing in either direction. A
separate adjustment is made for the leading edge and
for the trailing edge, so that the "lead" crown is slightly
higher than the trailing or "finish" crown. As material
moves under the screed during paving this differential
between crowns increases the density of the surface
and imparts a smooth texture.
NOTE: The crown adjustment is one of
the more important adjustments on the
paver. Mat imperfections can often
be corrected by changing the
adjustment of the lead crown!
Two gauges on the screed provide a crown
Screed Bottom with Crowning Arms
referencing ability for the operator. A more accurate
Figure 9
fine-adjustment gauge is located on the rear crown
turnbuckle screw. (See Figure 11).
Crown Adjustment Gauges
Figure 11
Page 56