Autoquip FREIGHTLIFT FLH - Manual (Page 15)

15
HYDRAULIC VELOCITY FUSES
Each hydraulic cylinder has a hydraulic velocity fuse (HVF) installed in the cylinder
ports. These HVFs are installed in the predetermined hydraulic oil flow velocity as the
oil returns to the reservoir. Should a catastrophic rupture or breach occur in the
hydraulic system and oil flows through the breach that exceeds the HVF rating, the HVF
will trigger and lock up. This lock up will occur within one to two inches of downward
movement of the platform carriage.
NOTE: Air in the system will also cause a lock up. Air acts like a spring when
compressed. To remove air from the system, see “Air Bleeding Procedures” in the
General Maintenance section.
NOTE: Small, slow fitting leaks will not trigger the HVFs. In an air-free system, the
breach must be large enough to cause an uncontrolled or destructive lowering speed.
Should a triggering and lock up occur, it can only be released by applying upward
hydraulic flow in a functional system.
WARNING !
Never run the unit with the gates or doors open! Do not operate the unit
with the doors open or with the interlocks “defeated” (bypassed)!
SAFETY RELEASE BYPASS VALVE (SRBV)
The SRBV is a part of the hydraulic system. Should the system pressure exceed the
predetermined pressure setting, the SRBV will bypass the pump output back to the oil
reservoir. The SRBV is factory set to the proper pressure, which will prevent damage to
the mechanical, hydraulic, and electrical systems due to overloading, obstruction, or
other circumstances.
SAFETY FEATURES