1.12.6. Hydraulic Cylinders. Several equipment
motions are controlled by hydraulic cylinders. The
location and description of these cylinders are as follows:
Hopper Lift Cylinders. The hopper lift cylinders
raise or lower the hopper wings to receive material from
a material handling truck, or feed material into the
conveyors. The hopper lift cylinders are located on each
side of the hopper. The cylinders are controlled from
the operator switch panel.
Tow Point Cylinders. The tow point cylinders are
used to raise or lower the leading ends of the screed tow
arms to change the screed tow point. This adjustment
changes the depth of the attack angle adjustment. The
tow point cylinders can be controlled from switches on
operator switch panel and screed control panels.
Hydraulic oil to the tow point cylinder is through a manual
shutoff valve and a pressure relief valve. When the tow
point cylinder is not used (disconnected) and the screed
tow arm pinned, the shutoff valve should be closed to
prevent movement of the tow point cylinder. The relief
valve allows for relief of excessive pressure from
damaging the tow point cylinder should the screed run
over an obstacle causing pressure on the tow point
Screed Lift Cylinders. The screed lift cylinders
raise the screed to the travel position and lower the
screed for paving. The screed lift cylinders are
controlled from the operator switch panel. When in the
raised position, the screed travel lock valve must be
closed for safety. Closing the screed travel lock valve
closes the lift cylinder bleed circuits, allowing the screed
to be raised, but not lowered. The screed travel lock
valve must be partially opened and screed lift switch
placed in the down, FLOAT, position to lower the screed.
extension cylinders are located inside the main screed.
The extension cylinders move the extension screeds in
and out. This function is used to widen or narrow the
width of the screed contact surface. The screed
extension cylinders can be controlled from the operator
switch panel and the screed control panels.