OP-755 Part 2 Pages 197-401 - Personal Page of GENE SLOVER

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scri bed on the s truc tual foundations. These alignment marks
are for purpose of ini tial installation and realignment check.
The Carriage
5. The carriage is a large assemblage that is mounted
on the roller paths of the two rail brackets. It includes two
large bearings in which the range finder instrument is supported
by radial and thrust roller bearings. The bearing centers
are spaced twenty-five feet. Each bearing consists of a bearing
bracket, a bearing cap and a roller bearing cage. These
have rigid mounting on the top surface of the respective right
and left roller and pinion brackets. The latter brackets include
roller path rollers and holding down rollers which ride
on. the arc-shaped rail surfaces of the rail brackets. The two
bearings,· thus arranged, are transversely connected by a beam
weldment of box-section (15 inches square), 19 feet 11.50 inches.
long, which spans the space between the rail brackets and
is bolted at each end to integrally cast flange seats in the
bearing brackets ..
. 6. On this carriage assembly are mounted the deflection
operating mechanism, . the deflection locking device' and
the al ti tude mechanism. Bearing rings on the range finder
seat in the bearings so that the instrument has rotative mounting
on eight large rollers in each bearing cage. Each bearing
cap has two rollers which bear on the upper sector of the ins
trument to hold it down. The left bearing cap has one roller,
centered at the top of the cap, in thrust position between
two lugs on the instrument bearing ring. The arrangement of
this left bearing is shown on drawing number 217224.
Altitude Mechanism
7. Rota tion of the range finder in the bearings to
give altitude adjustment to the instrument is performed by
means of an alti tude mechanism. This device, shownon drawing
number 217228, is a system of two handwheel altitude adjusting
inpu ts which respec ti vely drive two sides of a differential
gear. The output of the differential is a pinion meshed with
an arc rack that is attached to the instrument near the left
bearing ring. One handwheel, located at the range finder
pointer's station, provides altitude adjustment at 120 speed,
the other handwheel is located at the range finder operator's
s ta tion and func tions for fine setting at 182 speed+. Total
alti tude movement is 30 .degrees, 15 degrees above and below horizontal
line of sight. The movement has no provision for locking
at mi.d=posI tion. However, the design of the system worm
. worm-wheel drive and the balanced arrangement of the instrument
precludes overhaul so that altitude settings remain as set.
* These handwheelspeeds equal output pinion speed of eight and instrument
rotation of approximately one.
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