THE COLLIERY GUARDIAN

'	' AND

JOURNAL OF THE COAL AND IRON TRADES.

Vol. CXHI. ’	FRIDAY, MARCH • 30, 1917.	No. 2935.

AERIAL WIRE

By J. W.

The simplest form of ropeway is the type used by the
coastguard service in saving life from wrecked vessels.
There is simply one single wire rope stretched from the
ship to the shore, a one- or two-wheeled runner carry-
ing a buoy, in which the passenger is slung, and this
carrier is traversed backwards and forwards from ship
to shore, and vice versa, by means of a tow rope
fastened to the carrier, and pulled backwards and for-
wards by manual labour. A form of this type of rope-
way, with, free gravity haulage, has also been used for
archaeological excavations. The ropeway is laid on a
gradient, the one single carrying rope falling from the
loading end, whilst at the depositing end the rope
simply passes over a pair of crossed timbers, and is
anchored down to the ground beyond. There is no
hauling rope. The carriers consist simply of a single
wheel in a very light iron frame, terminating in a pair
of hooks, the whole running quite freely on the carry-
ing rope. The filled baskets are hooked into the two
hooks of the free running carriers, which then run
down the rope by gravity, and on reaching the tipping
point are caught by a man on a wooden platform,
and detached from the rope, the whole—carrier,
basket, and contents—coming to the ground. The
manual efficiency of this arrangement is very low, but
the installation is very cheap and easily rigged up,
and moved about from place to place, as tipping
proceeds.

Another development of this type is used for carry-
ing away and automatically dumping slag and ashes
from destructor furnaces, the traversing of the carrier
out and home being effected by means of an endless
haulage rope driven by an electric motor. The carry-
ing rope is carried along, in front of the furnace doors,
then over steel supports to the tipping ground. The
endless hauling rope makes 2| turns around an elec-
trically-driven fleeting wheel in the furnace house,
and at the return end passes over two vertical sheaves,
and round a tension sheave. A weight is hung from
this tension wheel to take up the slack of the hauling
rope, and keep it constantly up to its work. The
carrying bucket hangs from the two-wheeled carrier
in such a position that the slag can be raked out of
the furnace directly into the bucket. The electric
motor is then started by moving over a switch, and the
carrier travels outwards to the tipping ground. At
the point of tipping, a steel frame, which is suspended
from the main carrying rope, carries a trigger, which,
as soon as the bucket comes along, engages a lever on
the bucket, and throws over the catch which keeps the
bucket in position; arid, the trunnions of the bucket
being fixed below the centre of gravity of the .bucket,
it capsizes, and the contents fall to the ground. A
loop of the hauling rope near the driving motor is
passed once round a sheave, which is connected to a
train of wheels actuating a dial provided with a finger
and so arranged that as soon as the bucket is tipped,
this finger engages the starting switch, and throws it
over, thus breaking the electric circuit, and auto-
matically stopping the bucket, after tipping. The
starting switch and reversing switch being then moved
over, the empty bucket is returned to the furnace
house, where it is again automatically stopped, and
stands ready for its next load. As tipping proceeds,
the tipping frame is moved further along the carry-
ing rope, and at the same time the tripping finger on
the stopping dial is moved to a new ppsition to’allow
the carrier to run out the necessary greater distance
before being automatically stopped.	'

Provision has also been made for the automatic
return of the carrier, as well as automatic stopping,
preferably by a mechanical form of reversing gear.
The fleeting wheel driving the haulage rope is con-
nected to the first motion shaft by means of two bevel
wheels, adapted to gear with a clutch, and driving the
haulage drum through worm reduction gear. The
clutches are controlled by a screw connected to a dial
plate,*so that after so many revolutions of the con-
trolling screw, one clutch goes out of gear and the
other comes in, and thus reverses the motion of the
hauling rope automatically, f Where quicker hauling
speeds are desired, a system of open and crossed belts
has been introduced, which works exceedingly well.

The next development in this system was the provi-
sion of two carrying ropes instead of one, with a
separate carrier running backwards and forwards on
each rope, x This had the distinct advantage, where
there was any difference of level's at the ends, that the
carrier running downwards assisted the rising carrier,

* From a paper read before the South Wales Institute of
Engineers,	'

ROPEWAYS.’

WHITE.

and, in fact, where the gradient is "sufficient, and in
favour of the load, the descending loaded carrier hauls
up the ascending empty one, thus dispensing alto-
gether with driving machinery.

If the gradient is fairly even throughout, and is
sufficiently great, an ordinary tail rope attached to
each carrier is sufficient, but in some cases it is neces-
sary to make the hauling rope endless, and to pass it
over return sheaves at the delivery end, the top end
of the hauling rope being passed 21 times around a
fleeting wheel, provided with a brake, to regulate the
speed of descent. Where the carrying rope is sup-
ported by a standard, saddles are supplied on the
cross heads of the standards, the top of the saddles
are grooved out to exactly the diameter of the rope,
to prevent flattening of the rope under the passing
load, and the saddles made long enough, and curved
to form an easy bearing for the rope, some 2 ft. or
.more long, and suitably ramped off at each end to
prevent any kinking at the moment that the carrier
wheels pass from rope to saddle, or from saddle to
rope.

This system of the descending load assisting the
ascending one has latterly been applied even to the
one single carrying rope. Two carriers are used, with
an endless hauling rope, and a ramp is fixed over the
wheels of each of the carriers, so that when the two
carriers meet in the middle of the run, the descend-
ing carrier keeps to the rope, whilst the wheels of the
other pass along the ramp and over the wheels of the
first carrier, thus allowing the carriers to pass each
other. This arrangement doubles the carrying capa-
city of the single rope..

In another form of single-rope ropeway, more gener-
ally known as cableway, or Blondin ropeway, the load,
in addition to being traversed backwards or forwards
on the one rope, can also be raised or lowered. In
the simplest form, the load can only be raised or
lowered at the ends near the supporting towers, or at
fixed points along the rope where the spans are rela-
tively short ones. In this case, in addition to the
main carrying rope, there is only the combined
traversing and lifting rope, the one rope performing
both functions, and the load in transit being actually
hook-borne from the carrier or monkey which runs
backwards and forwards on the main - carrying rope.
Very heavy loads up to 20 tons can readily be carried on
this system. Although only relatively short spans can be
used effectively, the driving gear is very simple. In
the more advanced form, long spans up to 1,000 ft. or
..so can be negotiated, and the loads'raised or lowered
at any point along the whole span. This arrange-
ment, however, requires complicated and expensive
driving machinery and three additional ropes, viz. :
the raising, and lowering rope, the traversing rope,
and a fixed rope called the button rope, so called
because at intervals of every 60 ft. or so, along the
rope, buttons of constantly increasing diameter are
fixed.

When the carrier is in the centre of a long span,
with no load on, and it is .desired to lower the empty
bucket down to the ground, there is little weight on
the lowering rope, and it will sag considerably between
the carrier and the head mast, so that there is more
weight in the sag of the rope than at the lowering
end, and consequently the empty carrier bucket will
not descend. It is therefore riecessary to hold up the
intermediate loop of the hoisting rope to prevent this
excessive sagging, and this is done by using a series
of light carrier frames, which are supported on a kind
of horn on the trailing side of the main carrier, when
this latter is at home near the head mast. As this
carrier is drawn outwards towards the return .or tail
mast, it sheds one of these light frames as it comes to
each successive button on the button rope... Each light
carrier frame is provided with’ a slot, the slot on each
successive carrier being slightly larger than the pre-
ceding one, in the same proportion as the size of the
buttons on the button rope, so that as the first carrier
frame comes to the first button, -this latter engages in
its slot and holds it there, the slots on all the other
frariies being large enough to go through the button.
Then at the next button the next frame is detained,
and so On the whole length of the outwards run. At
the bottom of each carrier frame is a'small, sheave,
on which the hoisting rope is supported, and which
thus holds up this rope at intervals of 60 ft., and thus
prevents any long length of sagging rope from accu-
emulating. ■ When the carrier is run inwards again,
the projecting horn, which is now on its facing side,
picks up the carrier frames, and stores them in readi-
ness for the next outwards run. This type of cable way

works very efficiently,1 and is very largely used in
quarries for bringirig out the stone, etc., but is not
convenient for heavy loads, the hoisting rope being of
necessity fairly light and flexible, in order to keep the
size of the hoisting drums within reasonable limits.

For larger loads, other forms of “constant direc-
tion.” ropeways must be used, one of the best known
types of which is the single rope or mono-cable system.
In this form, one rope is used both to carry the weight
of the loads and the carriers, and also to transport
them from one end of the line to the other and back
again. This rope is spliced endless, and at the driving
end passes round single- or double-grooved driving
wheels, from 6 to 12ft. in diameter; whilst at the
return end, the end loop of the rope passes around a
return wheel, which keeps a constant tension on the
rope.

If the distance between the two terminals is greater
than about 100 yds., intermediate supports of wood or
steel are introduced to support the rope. On.the cross
heads of these supports, sheaves are fixed, over which
the rope passes, the usual practice being to put four of
these sheaves on the loaded or outwards side of the
rope, and two sheaves on-the empty side. The sheaves
are fixed on compensating arms, to facilitate the
passage of the loaded carriers, and to reduce the\
weight and rope wear on any one sheave.

The rope being set in motion by driving gear in the
ordinary manner, the next consideration is the attach-
ing of the carriers to the rope. After various devices
had been tried, it was found desirable to suspend
the carriers from a saddle, hung on the top side of
the rope, and provided with some means for increasing
the adhesion between the two. Probably one of the
best of these expedients was the introduction of a
short stud or nib of metal,, in the top side of the groove,
which was made of U shape, instead of V shape, the
diameter of the bend of the U being only fractionally
smaller than the diameter of the rope. On fairly level
lines, this saddle works very well, especially if care be
taken to follow up the wear on the rope by closing in

. the sides of the saddle to properly fit the rope.

Another form is the movable type of gripper saddle,
which is in two parts : an outer fixed jaw, and an inner
movable jaw. The movable jaw is connected by toggle
links to the fixed carrier head in such a way that when
the load hangs upon the rope, the whole weight of the
load rests upon the top pivot of the toggle joint, and
forces the movable jaw outwards towards the fixed
jaw, and tightly embracing the rope. At either of the
terminals two small wheels engage on to the fixed run-
rail,. and take the weight off the toggle joint, thus
allowing the jaws to open and the saddle to leave the
rope. This form enables gradients to be taken that
would be too severe for the fixed type of saddle,
besides allowing automatic return of the empty
carriers at the return end of the line. At each ter-
minal of the line is a bow-shaped rail, leading from
one rope to the other, so as to complete the circuit all
round for the carriers to run upon. For this purpose,
each carrier is fitted with a pair of small wheels along-
side the saddle itself, so arranged as to engage on this
bow-rail or run-rail, on which the carriers stand whilst
being loaded. They are then run by hand around to
the outgoing rope, upon which the saddles automatic-
ally engage, and are at once carried on, off the run-
rail, by the moving rope—the end of the run-rail being
ramped off for-the purpose. On arrival at the return
end, the wheels of the carrier engage on to the
incoming end of the run-rail, and if the carriers have
not been automatically tipped en route, they are' run
.by. hand on to the discharging point, where the con-
tents are tipped, and the carrier is then-run around
on. to the outgoing. end of; the return rope, on which
the saddles automatically engage again; and so the
carrier, returns once more to-the loading rail. «•

In the'case of ari angle station, whether the rope
itself goes through the angle around" suitable guiding
sheaves, or whether two separate ropes are used, as is
sometimes ’ the case, it is necessary to connect the
adjacent tangents of the rope by means of a curved
length of run-rail, on to which each carrier runs and
disengages itself from the carrying rope, in the same
way as at the terminals. This curved rail is gener-
ally placed at a sufficient gradient so that the carrier
runs along it by gravity, with sufficient way on it to
carry it on to the next outgoing rope, on to which it
engages in the same manner as already described. In
theory, the carriers should go through this angle quite
automatically, and in practice probably 99 out of 100
do so—but the odd carrier sometimes “ misses stays,”
and makes it necessary to have someone constantly in
atteridance. It is also rather difficult to provide for
automatic tipping of the carrier by this system,
especially in the centre of a long span.	'

Where complications arise^ such as severe gradients,
heavy loads, automatic angles, automatic tipping, and