OP-769 16" Three Gun Turrets Part 2 - Personal Page of GENE ...

OP 769 16 INCH THREE GUN TURRETS
are mounte d in a common valve block near the A-end.
They are spring-operated, plunger-type, s aIety
relief valves. The valves open and bypass excess
pressu.re flow to the expansion tank when the servo
and s upercharge discharge lines are overloaded. The
servo r elief valve is farthes t from the valve block
mounting plate and the supercharge relief valve is
nearest the mounting plate.
Expansion tank. The 28 . 5-gallon expansion tank
for each e levahng gea r asse mbly is a vent ed type
with gravity feed connection t o t he servo and supercharge
pumps . Retur n lines lead t o the tank from the
A-end, the B-end, and the s e rvo and supercharge
r elief valves. Located at the highest point of the hy ­
draulic system, t he tank body is box-shaped, 30.0
inches high, 20. 0 inches wide, and 10.0 inches deep.
It is equipped with a cover , high- and low-level trycocks,
fille r cap, and an oil strainer inside the tank.
The tank dissipates heat from the oil returned by the
reCirculating s ystem.
Oscillating bearing as sembly
The oscillating bearing (fig. 5- 5) is an enclosed
elevating-nut pinion-drive -type assembly. The
drive pinion engages the drive gear , which is keyed
to the elevating nut . The e levating screw is t hreaded
through the elevat ing nut and is attached to the gun
slide with a pivot pin. The elevating screw is fixed
a nd cannot rotat e . The elevat ing nut is rotate d by
the drive pinion, and causes vertical movement of
the elevating s crew to elevate or depress the gun.
The trunnion-pivoted oscillating bearing (fig. 5-
35) is aligned with the B-end with the axis of the
e levating screw offset 21. 0 inches from the vertical
plane of the gun bore axis . The trunnion bearing
blocks of the bearing form a foundation weldment
above the pan floor in the forward part of the gun
pOckets.
Components. The oscillating bearing assembly
compnses the following:
Bear ing and elevating nut
Elevating s crew
Oil s hield
LubricatIon pump
Lubrication tank
Bearuw and elevating nut. T he oscillating bearing
assem 1y is enclosed WIthin a hollow cast steel
b lock with integral trunnions (fig. 5- 5). The oscillating
bear ing houses rOller-type thrust bearings at
each end that s eat in the upper and lower adjus ting
nuts. The oscillating bearing t runnion adjacent t o
the B-end is bored t o r eceive t he drive pinion with
its two taper ed radial bear ings. The drive pinion
and drive gear a r e also enclos ed within the bearing
hous ing, together with the elevating nut.
The drive gear is keyed to the radially split ele ­
vating nut. The two halves of the elevating nut lock
togethe r for rotation but have adjustable axial motion
to eliminate end play of the elevating screw. The
lowe r half of the elevat ing nut is driven by the concentrically
m ounted drive gear , which is meshed
with the drive pinion, as s hown in figure 5-5. These
parts are adjusted by means of adjust ing nuts that
thread into the top and bottom ends of the bearing
hOUSing.
Elevating screw. The e levating screw has a
7. 75-inch outside diameter with right-hand double
5-10
threads of 1. 50-inch pitch. It is 153 inches long
overall, with 133 inches thr eaded, and with a lead
of 3 inches . The e levating s crew is secured to a
rear end bracket (fig. 5-36) of the gun s lide by a
bronze pivot pin at its upper end (chapter 4).
Oil s hield. A cylindrical oil shield (fig. 5-5) fits
around the e levating s crew and is attached to the upper
adjusting nut by 10 screws. The adjusting nut
has 20 equally spaced and threaded holes t o permit
the oil shield and the lubr ication pump oil lead to be
attached in appr Oximately the s ame position with a ny
s etting of the adjusting nut.
Three wiper elements within the oil shield a r e
threaded t o mesh with the elevating s crew. The wiper
elements are secured t o and r otate with the e levating
nut to r emove oil from the emerging elevating screw
threads. The oil drains downward through the bearing
assembly to a cylindrical s crew cover bolted to
a flange of the lowe r adjusting nut. Oil drains from
the cover into the screw pocket .
Lubrication pump. The lubrication pump (figs.
5-5 and 5-37) is an independent unit mounted on the
e lectric deck adjacent t o the gun layer's st ation
immediate ly below the el evating screw pocket and
lubrication tank. The pump pr ovides circulating
lubrication for the elevating sc rew and oscillating
bearing assembly. The pump is a r otary gear-type
unit, attached t o and driven by a horizontally mounted
1/ 4- horsepower electric motor at the rate of 600
revolutions per minute. Pump de liVery, at the rate
of 3 gallons per minute unde r an operating pressure
of 50 pounds pe r square inch, Is controlled by a
spring-loaded relief valve.
Lubrication tank. The lubrication tank (elevating
s crew pocket) is a flanged steel assembly attached
to the underSide of the pan floor that extends downward
to the elect ric deck, as shown in figure 5-37.
In addition to furnishing storage fo r the lubricant,
the tank weldment also forms a pocket for the elevating
screw. An oil pipe connects the tank s torage
space with the inlet of the pump . The pressure outlet
of the pump is connected by an oil pipe t o a fitting
in the oil shie ld.
E levating gear controls
The independent elevating gear control arrange ­
ments for each of the three guns of the turret consist
of:
Start-stop control
Power-drive transmiSSion control
Control selector
Ser vo stroking system
Control gear hand gear
Control gear response gear
Cont r ol box mechanism
Receiver-regulator
Start-stop control. Each elevating gear power
drive is started and stopped through its electricpower
motor controlle r (described on page 5-4).
The controller is remotely operated by two push buttons
adjacent t o the gun laye r 's station. One push
button is labeled START-EMERG and the othe r STOP.
Pressing the START-EMERG button closes a
normally open, three-pole switch and energizes the
coil of the main contactor to connect power to the
electric motor. Holding cont acts on the relays keep
the power Circuit closed when the START-EMERG