Owner`s manual

26
Example #2
The curb form to be used is Curb Form Design (CFD)
#1021. The area of this curb form is 25 square inches
and the overall height of this curb form is 4”. Referring
to the chart above see the area of #1021 curb form falls
within the 18 to 32 square inch recommended range of
a 5” diameter auger. Then see that both the height and
width of this curb form also fall within the
recommended range for a 5” diameter auger. Because
the height and width of this curb form also fall within the
recommended height and width range of a 6” diameter
auger the temptation might be to use a 6” diameter
auger to achieve greater production/speed. However,
for best overall results in terms of production, life of
wear parts and curb quality, a 5” diameter auger is the
better choice.
The most common mistake in sizing a curb form to the correct auger size is choosing a curb
shape, which is too small for a particular auger. In example #2, the previously mentioned curb
with an area of 25 square inches would work well with a 5” diameter auger assembly, but would
most likely not work at all with a 6” diameter assembly.
The amount of material discharged by the 6” diameter auger into the curb mold would be so
great in relation to the curb size that the mold would not be able to discharge or extrude the
material fast enough. In effect, the mold becomes a “BOTTLENECK.” As a result, excessive
pressure will be created inside the form. When the density of the material in the curb form
reaches the point where it can be compacted no further, the excessive pressure in the form will
be transmitted back through the drive train, causing repeated disengagement of the safety
torque arm, raising up of the curb form and/or shear bolt breakage. To avoid the problem, the
auger size must be reduced or the curb form size increased.
The second problem in sizing curb sections to auger sizes is choosing a form that is too large
for a particular auger. An undersized auger can discharge enough material to propel the
machine, but the curb produced will have inadequate density, a curb surface full of voids and/or
a curb that will not stand up. In the most severe cases of an undersized auger, the auger will not
discharge enough material to propel the machine. An undersized auger can be corrected by
either increasing the auger size or by reducing the curb form area.
Possible exceptions:
If the curb form size is within 5-10% the recommended ranges in either upper or lower limits in
the chart above the curb form may operate with the mix in your area. Only tests with local mixes
will confirm satisfactory performance. Be aware that operating a Curbilder with an auger size
OUTSIDE of the recommended limits can cause excessive wear and/or insufficient curb density.
THE CUSTOMER ASSUMES ALL PERFORMANCE AND WEAR ISSUES WHEN
OPERATING THE CURBILDER WITH AN AUGER OUTSIDE THE RECOMMENDED
RANGES.
CFD # 1021 Area 25 SQ IN
Auger Size 5 ”
140 Linear Feet per CU YD of concr
e
78 Linear Feet per Ton of Asphalt