Autoquip FREIGHTLIFT FLHC - Manual (Page 69)

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2. The rotating motor shaft is mechanically coupled to a positive displacement gear
pump. The pump will rotate, drawing oil from the reservoir, pressurizing it, causing
flow through the check valve, and out to the cylinders through high pressure hoses.
The incoming volume of oil flows to the rod side of the cylinder pistons, causing the
rods to retract into the cylinders.
3. Attached to the cylinder rods are double sheave clevis blocks. In the sheaves are
wire ropes (one on each of the masts). One end of the wire rope is terminated at
the upper mast, reeved through the five sheaves, with the other end terminated on
the platform carriage (this is called “4 part reeving”). Therefore, for every inch that
the rods retract into the cylinders, the carriage is raised 4”. The platform carriage is
guided in the two vertical masts by rollers that are captured on opposite sides of the
mast flange.
4. When the carriage arrives at the upper landing, the top channel of the carriage
makes contact with the adjustable stops and the hydraulic system builds pressure.
The pressure switch senses this increase in pressure, and shuts off the motor.
NOTE: The locking cams mounted to the carriage will be engaged only if the cable
breaks.
WARNING !
Do not over travel! Mechanical stops must be in place to prevent the
carriage from over traveling. Over-traveling can cause permanent damage
to the carriage or failure of the lifting cables.
DOWN
1. Pressing the DOWN push-button will permit 115-volt control power to be applied to
the down solenoid coil that is on the control valve.
2. The coil causes the core plunger to move outward, allowing the down valve to open
and the pressure-compensated down speed regulator to regulate the degree of the
valve opening. This is dictated by the weight of the load placed on the platform
carriage. The cylinders extend as the loaded carriage descends under its own
weight and oil is forced out of the rod end of the cylinders through the down flow
controls and back to the storage tank. As the cylinder extends, it also allows cable
to be fed back through the reeving system and hold the carriage as it descends.
OPERATING INSTRUCTIONS