Manitowoc Published 10-01-12, Control # 044-05 v2 3-61
777 OPERATOR’S MANUAL OPERATING CONTROLS AND PROCEDURES
3
HYDRAULIC SYSTEM CONTROLS
This topic identifies location and function of hydraulic
components Manitowoc has provided for the Customer
Supplied Pile Driving System.
See Figure 3-35 for location of hydraulic components.
Components Function
Hydraulic Tank
The hydraulic tank is mounted on left side machinery
enclosure. It houses the hydraulic oil for the system.
A sight gauge and level decal are provided on outside of
tank.
Tank contains a 100-mesh suction screen which prevents
large pieces of foreign matter from entering pump.
Hydraulic Pump
The pump is mounted on and driven by the 777 front drum
pump.
The pump is a gear type with a flow rating of 42 gpm (159
liters/min) at 3,000 rpm, when engine is operated at high
idle.
Directional Control Valve
The directional control valve is mounted on front of rotating
bed. The valve has four sections:
• Inlet section which routes oil from pump to two work
sections (A and B) of valve and routes return oil flow
from work sections through filter back to tank.
The inlet section has a relief valve which limits system
pressure to 3,000 psi (207 bar).
• Two electrically controlled work sections that are spring
returned to neutral. The work sections direct oil flow to
customer supplied cylinders in response to controls in
operator’s cab.
- Work sections A and B have a 4-way, 3-position
spool for controlling a cylinder. When in neutral,
work section valves A and B lock cylinders in
position and allow oil flow to customer supplied
spotter system control valve. When enabled, work
station valves A or B direct oil flow to customer
supplied cylinders. Return oil from cylinders flows to
inlet section then through system filter and back to
tank.
• The end cap routes return oil back to inlet section or to
spotter system.
Hydraulic Filter
The hydraulic filter is mounted along side directional control
valve in return line to tank.
The filter has a 10-micron, spin-on type element with a visual
service indicator.
Spotter System Dump Valve
Spotter switch is a 2-position maintained rocker, located on
operator’s cab upper left wall. The Spotter switch controls
operation of 2-position dump valve. The lock on rocker must
be moved up before rocker can be placed in ON position.
When Spotter switch is ON, green SPOTTER light on front
console comes on. The dump valve closes to allow oil flow
from directional control valve to spotter system control valve.
When rocker is placed in OFF position, green SPOTTER
light goes out. The dump valve opens to allow oil flow
through the system filter and back to tank.
NOTE: When one or both directional control valves are
operating, oil available to operate spotter system is
greatly reduced.
Cylinder Operating Controls
The controls are 3-position, handle-operated electric valves
which provided variable control of the customer supplied
cylinders.
Handle A controls forward and reverse operation of the A
work section of directional control valve. Handle B controls
forward and reverse operation of the B work section of
directional control valve. Exact operation of controls
depends upon how the customer connects the hydraulic
lines to cylinders.
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