Hydraulic
System
The STC 140 is designed for use with an open center
hydraulic system when equipped as standard. The system
requires an approximate 16.5 horsepower to supply
10 gallons per minute and 2350 PSI. Power supply is
generally a direct mounted pump and PTO for truck
chassis applications, however other power supplies
can be utilized. Crane utilizes a seven section, stackable,
directional control valve. Four sections are solenoid
operated for remote control of crane boom functions.
Three manual sections operate the outrigger functions.
A relief valve is incorporated into the valve inlet.
An additional port allows installation of an electro-hydraulic
proportional speed control cartridge into the valve
inlet, providing remote crane speed control with no
alteration of hydraulic system plumbing.
Holding Valves
The base (extension) end of boom lift and extension
cylinders are equipped with pilot operated counterbalance
valves built into the cylinder. The counterbalance
valve provides protection from boom collapse in the
event of a hydraulic system failure or hose break.
In addition, the counterbalance valves smooth lowering
of the boom under load and also act as a thermal relief
to prevent excessive pressure build up due to thermal
expansion of the hydraulic oil.
Winch System
The winch is powered by a low-speed high-torque hydraulic
motor through a 42:1 ratio worm gear with an automatic
mechanical brake for load holding. Winch system is
equipped with 100' of 1/2" diameter wire rope. A ball
bearing swivel hook is provided for single line applications
and a 2-part line block is provided. Overhaul weights
may be optionally supplied.
Rotation System
Rotation is accomplished by a turntable bearing, driven
by a low-speed high-torque motor through a planetary
reduction gearbox. The drive incorporates a spring
applied, hydraulically released brake to lock the
system when not functioning. A mounted valve block
controls brake release and reset, and also provides
counterbalance valves to control smoothing of rotation
operation and prevent over-running loads when the
crane is rotated on an incline.
Overload Protection
An active overload protection system is standard.
The system senses overload conditions and prevents
operation of boom extend and winch raise functions
in the event of an overload. Boom retract and winch
lower functions remain operational and allow crane
operation to alleviate the overload condition. When
systems are within rating limits the system will automatically
reset to normal operation.
Controls
Equipped as standard, control of the crane is provided
by a hard wired remote pendant providing on-off operation
of crane functions. Switches provided are military
spec sealed toggle, capable of reliable operation
in harsh operating environments which may be encountered.
Optional Equipment
Electro-Hydraulic Flow Control
System provides an electrically controlled variable
flow control valve which is operated at the remote
control pendant. The valve will allow control of the
oil volume supplied to the crane directional valve
and therefore will control the crane function operating
speeds. This system uses the same control switches
as the standard on-off control in conjunction with
a variable controller to regulate crane function speeds.
Control Pendants
The standard remote pendant can be equipped with a
rotary actuator for control of electro-hydraulic flow
control system described above. A hard wired pendant
may be optionally supplied which uses an index finger
trigger actuator for true one hand control of all
crane functions and function operating speeds. A radio
remote control is also available which provides operation
of the crane without wired cables and allows complete
freedom of movement. The unit is FCC approved and
uses a multiple coding system to eliminate any possibility
of accidental operation. The radio remote may be equipped
for on-off or remote speed control operation.
Stabilizers
Stabilizer systems can be provided in manual or hydraulic
versions. A standard configuration is available or
a custom design can be provided for specific requirements.
Winch Options
Optional worm gear or planetary winches can be supplied
in single speed or two speed versions which can provide
line speeds of more than 100 feet per minute single
line.
Other Options
A variety of other equipment
accessories and options can
be provided to meet the needs of specific applications.
Special equipment includes lifting hooks, flow adjusters
to allow user changeable selection of maximum crane
function speeds, inline relief valves, pallet forks,
grapples and other items too numerous to mention.
Please contact us for evaluation of any special requirements
you may have.
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