retraction engine nears the end of the retract stroke, the
retract dump valve is actuated. The dump valve closes
allowing the pilot-actuating fluid from the retract
directional valve to return to the gravity tank, initiating
the retract braking stroke.
VENT VALVE PANEL
The vent valve panel is located on top of the
retraction engine manifold assembly. Vent valves are
mounted on the panel and are connected to various
points in the retraction engine hydraulic system. These
valves are used to bleed (vent) air and air saturated
hydraulic
fluid
from
various
retraction
engine
components. A hydraulic fluid reservoir is located at
the bottom of the vent valve panel. The reservoir is used
to collect vented fluid and provide the outlet to return
vented fluid to the hydraulic system.
CABLE TENSIONER ASSEMBLY
The cable tensioner assembly (fig. 4-47) consists of
the four cable tensioners required to keep the retraction
engine drive system taut. Each cable tensioners consists
of a hydraulic cylinder containing a piston with a
threaded rod extending from one end and a rod
attaching a clevis/sheave from the other end. Fluid
under pressure from the cable tensioner accumulator
forces the tensioner sheaves toward the cylinders
applying tension to the drive system cables. The
threaded rods with adjusting nut on the other end of
each tensioner provide a stop for sheave stroke when
the pressure in the tensioner cylinders is overcome by
the braking action which occurs during dump valve
actuation.
4-39
PISTON ROD
CLEVIS ASSEMBLY
SHEAVE ASSEMBLY
RETRACT CYLINDER ASSEMBLY
ADVANCE CYLINDER ASSEMBLY
STOP NUT
LOCKING NUT
TENSIONER ACCUMULATOR (REF)
ABEf0448
Figure 4-47.—Retraction-engine cable tensioners.
