Topcon mmGPS 3D Paver, Reference Manual

Page: 169 / 288

Paver Components
P/N 7010-0781
4-7
Head of Material (“M”)
One of the primary functions of the paver tractor is to convey and
distribute paving material onto the ground in front of the entire width
of the screed. This material, once deposited in front of the screed is
the head of material over which the screed passes.
One of the keys to smooth paving is to maintain this head of material
as constant as is possible. The resistance to forward motion exerted
by the head of material (M) is one of the major component of
resistance to forward motion (Figure 4-10). Control of this force is a
basic and necessary function of any paving operation.
Figure 4-10. Head of Material Force (“M”)
The volume and consistency of the head of material determines how
much paving material flows under the screed and influences mat
thickness and surface texture.
The most common factor affecting force “M”, the head of material, is
incorrectly adjusting the Automatic Feeder Controls.
These systems, whether of the “hanging paddle” type or the sonic
sensor type, should be adjusted to operate the auger/conveyor
assemblies 95% to 100% of the time. On/off operation of the auger
system causes fluctuation in the head of material.
The highest quality mat is the general result when a constant head of
material is maintained across the entire width of the screed and the
material almost covers the auger shaft. If the volume of paving
material is too high, there is resistance to the travel of the screed. This
causes the screed to rise and can result in ripples, auger shadows and
long waves. It also results in increased auger wear (Figure 4-11 on
page 4-8).
Head of
Material
(Force "M")
M