Wire
Rope Classifications and Features
Number
of strands and construction
determine
wire rope classification.
Wires are the basic building blocks of a wire
rope. They lay around a "center" in a specified pattern
in one or more layers to form a strand. The strands lay
around a core to form a wire rope. The strands
provide all the tensile strength of a fiber
core rope and over 90% of the strength of a wire rope with
an independent wire rope core.
Characteristics like fatigue resistance and
resistance to abrasion are directly affected by the design
of strands. In most strands with two or more layers of wires,
inner layers support outer layers in such a manner that
all wires may slide and adjust freely when the rope bends.
As a general rule, a rope that has strands
made up of a few large wires will be more abrasion resistant
and less fatigue resistant than a rope of the same size
made up of strands with many smaller wires. The basic strand
constructions are shown below:
|
Single layer.
The most common example of
the single layer construction is a 7 wire
strand, It has a single-wire center with six
wires of the same diameter around it.
|
|
 |
|
Seale.
This construction has two layers
of wires around a center wire with the same
number of wires in each layer. All wires in
each layer are the same diameter. The strand
is designed so that the large outer wires
rest in the valleys between the smaller inner
wires. Example: 19 Seale (1-9-9) strand.
|
|
|
|
Filler wire.
This construction has two layers
of uniform- size wire around a center wire
with the inner layer having half the number
of wires as the outer layer. Small filler
wires, equal in number to the inner layer,
are laid in valleys of the inner layer. Example,
25 Filler Wire (1-6-6f-12) strand.
|
|
|
|
WarringtonThis
construction has two layers with one diameter
of wire in the inner layer, and two diameters
of wire alternating large and small in the
outer layer. The larger outer-layer wires
rest in the valleys, and the smaller ones
on the crowns, of the inner layer. Example:
19 Warrington [1-6-(6+6)].
|
|
|
|
Combined patterns.
When a strand is formed in a single operation
using two or more of the above constructions,
it is referred to as a "combined pattern".
This example is a Seale construction in its
first two layers. The third layer utilizes
the Warrington construction, and the outer
layer is a Seale construction. It's described
as: 49 Seale Warrington Seale [1-8-8-(8+8)-16].
|
|
