Clinch Valley news. [volume] (Jeffersonville, Va.) 18??-2019, 1893-02-24

! ingenious thing of the kind ever made.
1t has the superb record of lifting "A
seycnty-ton boiler off the pier, towing
itself II distance of 15o feet, and lower
ing the boiler with delicate adjustment
into the armorcd cruiser New York in
less than twenty-five minutes Oaly two.
mcn were required to operate the ma
chine, and the ease with which the
seventy ton bundle was lifted from one
place to another suggested play ,rather
than mechanical engineering Of high
grade.
AS the illustration shows, the derrick
is Il big cone. IN the apex OF which is
set huge mast, passing through the
AIMS of the machine, which stretch out
from the top of the cone. This some Is
simply series of steel uprights resting
on pontoon and enclosed with wood,
en- house Inside the house are four
engines of forty horsepower cac1 con
trolling the drum for the pulley cables
and the machinery for turning the arms
around and propelling the lifting pull.
leys towards the ends OF the main boom.
The height of the cone is sixty-hvc feet
1t is strongly braced, and, ON the
ground floor, is crowded with machin-
cry. The mast is iifty-onc feet high
above the boom. 1t is of steel, and mol
low, being three feet in diameter aud
bnced here and there inside with extra
thicknesses of metal. 1t rest in Il socket
on ball bearings, forty-two steel balls,
each four inches in diameter aud
absolutely true, being used in the rotary
motion OF the shaft and the long arms
Another set of balls is used at the can Of
the cone Tor lateral pressure rs the arms
swing around.
From three stay plates that hook
themselves over the top of the mast
strong guy gables stretch to the lifting
arm to prevent it from breaking.
The arm with which the lifting is
done is sixty-tive feet long and the
other is fifty feet long. They arc
made of "built-up" steel of the
toughest quality. The longer one
Is fitted with travelling machinery,
so that it may deposit its burden at any
required distance within its scope away
from the mast. The short arm is an.
chorcd to the foot of the cone by strong
cables, and when very heavy burden Is
lifted two long steel arms arc droppcd
from the outer end to the side of the
pontoon below.
The long arm is fitted with two sets of
pnlleys, one for light lifts and one for
heavy lifts. The pulley apparatus is
called the 'isling," aud is fitted with IL
inch wire ropes. There arc ten coils on
the heavy hoist and two on the light.
The pullcys of the heavy hoist are thirty
inches in diameter.
The pontoon Oh which the derrick
rests Is of iron and fitted with system
OF water compartments. 1t is thirteen
leet deep, sixteen feet long, aud sixty.
two feet wide. When boiler or any
heavy weight is to be hoistcd the water
is let in on the opposite side of the pom
toon SO, as to keep the derrick on an even
keel. AS the burden glides toward the
outward end of the lifting arm more
water is admitted, and before any low.
ering begins the machine is carefully ad.
justed and made level. The derrick is
fitted with, pumping machinery so that
when its burden is left in place the
water is pumped out. In admitting the
waterno pump is used. 1t is allowed to
run right in from the river.
The derrick is operated by the cngi.
neer in the third story. He has series
of levers like those in signal stations in
the block system of operating railroads.
At his back Is Steam gauge, showing
the condition of the boilers, and speak
ing tubes to communicate with his fire
man at the engines beneath. There is
large gong in the room, which is sounded
by the boss rigger, who supcrintcnds
from the pier the wrapping of the cables
about the object to be hoistcd and the
hooking of them to the pulley. The
signals tell the engineer when to stop,
go ahead, lower or lift. BY means OF
capstans on the pontoon the derrick can
tow itself about the shipyard. 1t Is a
tool that saves an enormous amount of
time and energy.