The compound laying machine must, however, be stopped each time that
the supply of yarn on any bobbin is so low as to call for a fresh one.
This would occur so frequently in the case of the larger ropes as to
offset the advantages just mentioned, hence the machine is used on a
limited range of sizes only.
As can be seen in the picture, the machine contains a vertical
shaft with upper and lower projecting arms which support the
bobbin-flyers--four in number in this particular case. The bobbins
within each flyer turn on separate spindles, allowing the yarns to pass
up through small guide plates and thence into a tube.
Each flyer is geared to revolve on its own axis, thus twisting its set
of yarns into a compact strand. At the same time all the flyers revolve
with the main shaft in an opposite direction and form a rope out of the
strands as the latter come together in a central tube still higher up.
The rope is drawn through this tube by a series of pulleys which exert
a steady pull and so keep the proper twist in the rope. From these
pulleys the finished product is delivered onto a separately-driven
coiling reel, an automatic device registering meanwhile on a dial the
number of fathoms run.
The small reel, seen near the head of the main shaft, holds the small
heart rope which is fed into the center of certain four-strand ropes to
act as a bed for the strands.
Pure Manila rope is the very best and the most satisfactory for all
around use. The character of good Manila fiber is such as to impart to
a properly made rope such necessary factors as strength, pliability,
and wearing qualities.
Regular 3-strand Manila rope is universally used for all general
purposes.
For certain special uses, however, and particularly where the rope is
to be used for any kind of sheave work, a 4-strand type of construction
will be found the most suitable, as such a rope presents a much firmer,
rounder, and greater wearing surface than the ordinary 3-strand. There
are many different types of 4-strand rope.
The picture shown on this page represents a coil of 4-strand Manila
called “Best Fall.” This rope is made of carefully selected fiber;
is 4-strand with heart, and is harder twisted than ordinary goods.
Best Fall is adapted for heavy hoisting work, as on coal and grain
elevators, cargo and quarry hoists and for pile-driver hammer lines.
~AN AVERAGE COIL OF ROPE--1200 FEET~
The standard length coil of rope is 1,200 feet, although extra long
lengths are every day made for such purposes as oil-well drilling, the
transmission of power, etc., etc.
[Illustration: SECTION, CROSS SECTION AND COIL, FOUR AND THREE-FOURTH
INCHES CIRCUMFERENCE. SECTION AND CROSS SECTION ONE-HALF ACTUAL]
[Illustration: DIFFERENT KINDS OF KNOTS