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 TM 55-1925-273-10-1
0039 00
The directional control valve (figure 8, item 4) permits the operator to choose the direction of rotation of the anchor windlass
as well as its speed of rotation. When the directional control valve (figure 8, item 4) is in the NEUTRAL position, the supply
line is CLOSED, and no supply flow is permitted to enter the anchor windlass motor (figure 8, item 8). At the same time,
both sides of the anchor windlass motor are OPEN to the return piping. When the directional control valve (figure 8, item 4)
is shifted toward the return spring, the supply is routed to the right side of the anchor windlass motor and the return flow
comes from the left side of the anchor windlass motor, causing motor rotation. When the directional control valve position
is reversed, flow to the anchor windlass motor is reversed, reversing the direction of anchor windlass motor rotation.
A counterbalance valve (figure 8, item 5) is installed between the directional control valve (figure 8, item 4) and the anchor
windlass motor (figure 8, item 8). The counterbalance valves act as a hydraulic brake to prevent the anchor windlass from
overrunning the anchor windlass motor. The counterbalance valves also ensure that the anchor windlass motor will only turn
when pressure is applied from the directional control valve.
A fail safe brake (figure 8, item 9) is fitted between the anchor windlass gear train and the achor windlass motor (figure 8,
item 8). This fail safe brake is a spring-applied, pressure-released design. In this design, an internal spring assembly applies
the fail safe brake until hydraulic pressure is applied to release it. In the anchor windlass circuit, hydraulic pressure is
supplied to the fail safe brake assembly any time that the directional control valve (figure 8, item 4) is moved away from the
NEUTRAL position. When the directional control valve is returned to the NEUTRAL position, the pressure is removed
from the fail safe brake and the springs apply the brake, providing a mechanical braking action to the anchor windlass motor
output shaft.
Output from the anchor windlass motor (figure 9, item 1; figure 8, item 8) goes through the fail safe brake (figure 9,
item 2; figure 8, item 9) and to the driveshaft (figure 9, item 3). The driveshaft turns the input shaft (figure 9, item 4)
of the worm gear (figure 9, item 5) that rotates the anchor windlass main shaft (figure 9, item 6). The main shaft is
permanently fixed to the gypsey heads (figure 9, item 7), therefore the gypsey heads rotate whenever the anchor
windlass motor (figure 9, item 1; figure 8, item 8) rotates. The wildcats (figure 9, item 8) can be connected to the
main shaft via a dog clutch (figure 9, item 9). The dog clutch permits the gypsey heads to rotate separately from the
wildcats, thus the lines can be handled by the gypsey heads without disturbing the anchor chains.
Manual braking is provided for the wildcats (figure 9, item 8) by band brakes (figure 9, item 10). Each wildcat is provided
with a band brake providing individual control for each anchor chain. The band brakes are actuated by turning the brake
handwheel (figure 9, item 11). The brake handwheel tightens the brake band around the wildcat drum (figure 9, item 12),
slowing or stopping wildcat rotation.
0039 00-14
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