This circuit is typical for many cable cylinder speed control
applications. The cylinder stroke in this schematic is common
for GREENCO units.
Energizing solenoid "A" flows
air through the 4-way valve and ball check to piston. As the
piston moves to the right the trolley attached to the load
moves to the left. Air inside the cylinder is forced out
through a metering valve. This circuit maintains a constant
back pressure on the piston an prevents lunging if the load
drops quickly or reveres. Metering-in and bleed-off circuits
work well when their application is required.
This circuit incorporates a high pressure hydraulic cable
cylinder. Oil is supplied form a hydraulic power supply at 500
PSI max. to a 4-way valve.
Energizing solenoid "B" flows
oil through a ball check to the cylinder's piston. Oil
inside the cylinder is regulated out for effective speed
control. Energizing solenoid "A" reverses the cycle. All
seals within the cylinder function more effectively with
hydraulic fluid added lubrication at these pressures.
|COMBINATION AIR-OIL CIRCUIT
This circuit combines the rapid operation of pneumatic
circuits and close control available in hydraulic circuits to
form effective machine circuits. This system is economical
because an adequate air supply is usually available.
Energizing solenoid "A" air
flows through the 4-way applying pressure on the oil in tank
No. 1. Oil flows through the check valve to the piston
moving it to the right. Oil inside the cable cylinders
regulated out by a variable flow control valve. This circuit
gives fine speed control.
This circuit incorporates a single-end CABLE-TROL unit
when gravity is used to lower a load. The load may be a heavy
door or something similar. Hydraulic speed control is needed,
however, rather than employing a hydraulic unit to power the
system, a more economical air system is used. To raise the load,
the 3-way valve is activated opening the reservoir to air
pressure. Oil is forced form the reservoir, through the check
valve, and into the cable cylinder forcing the piston to the
left and raising the load. Reversing the 2-way valve, air
pressure is blocked and gravity lowers the load at a rate of
speed governed by variable orifice.