Outer wires: All wires positioned in the outer layer of wires
in a spiral rope or in the outer layer of wires in the outer strands of
a stranded rope.
Inner wires: All wires of intermediate layers positioned between
the center wire and outer layer of wires in a spiral rope or all other wires
except center, filler, core and outer wires of a stranded rope.
Core wires: All wires of the core of a stranded rope.
Centre wires: Wires positioned either at the center of a spiral
rope or at the centers of strands of a stranded rope.
Layer of wires: An assembly of wires having one pitch circle
diameter. The exception is Warrington layer comprising alternately laid
large and small wires where the smaller wires are positioned on a larger
pitch circle diameter than the larger wires. The first layer is that which
is laid immediately over the strand center.
Note: Filler wires do not constitute a separate layer.
Tensile strength grade of wires: A level of requirement of
tensile strength of a wire and its corresponding tensile strength range.
It is designated by the value according to the lower limit of tensile strength
and is used when specifying wire and when determining the calculated minimum
breaking force or calculated minimum aggregate breaking force of a rope.
Wire finish: The condition of the surface finish of a wire,
e.g. bright, zinc coated.
Strands
Strand: An element of rope usually consisting of an assembly
of wires of appropriate shape and dimensions laid helically in the same
direction in one or more layers around a center. Round strand: A strand with a cross-section which is approximately
the shape of a circle.
Triangular strand: A strand with a cross-section which is
approximately the shape of a triangle.
Note: Triangular strands may have built-up centres (i.e. more than one
wire forming a triangle).
Compacted strand: A strand which has been subjected to a compacting
process such as drawing, rolling or swaging whereby the metallic cross-sectional
area of the wires remains unaltered and the shape of the wires and the dimensions
of the strand are modified.
Note: Bridons brands of Dyform rope contain strands which have
been compacted.
Single lay strand: Strand which contains only one layer of
wires, e.g. 6-1.
Parallel lay strand: Strand which contains at least two layers
of wires, all of which are laid in one operation (in the same direction),
e.g. 9-9-1; 12-6F-6-1; 14-7+7-7-1. Each layer of wires lies in the interstices
of the underlying layer such that they are parallel to one another, resulting
in linear contact.
Note: This is also referred to as equal lay. The lay length of all the
wire layers are equal.
Seale: Parallel ay strand construction with the same number
of wires in each wire layer, each wire layer containing wires of the same
size, e.g. 7-7-1; 8-8-1; 9-9-1.
Warrington: Parallel lay strand construction having an outer
layer of wires containing alternately large and small wires, the number
of wires in the outer layer being twice that in the underlying layer of
wires, e.g. 6+6-6-1; 7+7-7-1.
Filler: Parallel lay strand construction having an outer layer
of wires containing twice the number of wires than in the inner layer with
filler wires laid in the interstices wires of the underlying layer of wires,
e.g. 12-6F-6-1; 14-7F-7-1.
Combined parallel lay: Parallel lay strand construction having
three or more layers of wires, e.g. 14-7+7-7-1; 16-8+8-8-1; 14-14-7F-7-1;
16-16-8F+8-1.
Note: The first two examples above are also referred to as Warrington-Seale
construction. The latter two examples are also referred to as Seale-Filler
contruction.
Multiple operation lay strand: Strand construction containing
at least two layers of wires, at least one of which is laid in a separate
operation. All of the wires are laid in the same direction.
Cross-lay: Multiple operation strand construction in which
the wires of superimposed wire layers cross over one another and make point
contact, e.g. 12/6-1.
Compound lay: Multiple operation strand which contains a minimum
of three layers of wires, the outer layer of which is laid over a parallel
lay center, e.g. 16/6+6-6-1.
Ropes
Spiral
Rope:
An assembly of two or more layers of shaped and/or round wires laid helically
over a center, usually a single round wire. There are three categories of
spiral rope, ie. spiral strand, half-locked coil and full-locked coil.
Spiral Strand: An assembly of two or more layers of round
wires laid helically over a center, usually a single round wire.
Half-locked Coil Rope: A spiral rope type having an outer
layer of wires containing alternate half lock and round wires.
Full-locked Coil Rope: A spiral rope type having an outer
layer of full lock wires.
Stranded Rope: An assembly of several strands laid helically
in one or more layers around a core or center. There are three categories
of stranded rope, ie. single layer, multi-layer and parallel-closed.
Single Layer Rope: Stranded rope consisting of one layer of
strands laid helically over a core.
Note: Stranded ropes consisting of three or four outer strands may, or
may not, have a core. Some three and four strand single layer ropes are
designed to generate torque levels equivalent to those generated by Rotation
Resistant ropes.
Rotation-resistant Rope: Stranded rope designed to generate
reduced levels of torque and rotation when loaded and comprising an assembly
of two or more layers of strands laid helically around the center, the direction
of lay of the outers strands being opposite to that of the underlying layer.
Rotation-resistant Rope: catagory 1: Stranded rope constructed
in such a manner that it displays little or no tendency to rotate, or, if
guided, transmits little or no torque, has at least fifteen outer strands
and comprising an assemly of at least three layers of strands laid helically
over a center in two operations, the direction of lay of the outer strands
being opposite to that of the underlying layer.
Rotation-resistant Rope: catagory 2: Stranded rope constructed
in such a manner that it has significant resistance to rotation, has at
least ten outer strands and comprising an assemly of two or more layers
of strands laid helically over a centre in two or three operations, the
direction of lay of the outer strands being opposite to that of the underlying
layer.
Rotation-resistant Rope: catagory 3: Stranded rope constructed
in such a manner that it has limited resistance to rotation, has no more
than nine outer strands and comprising an assemly of two layers of strands
laid helically over a center in two operations, the direction of lay of
the outer strands being opposite to that of the underlying layer.
Compacted Strand Rope: Rope in which the outer strands, prior
to closing of the rope, are subjected to a compacting process such as drawing,
rolling or swaging.
Note: Bridons products containing compacted strands are identified
by Dyform, e.g. Endurance Dyform 6; Endurance Dyform 34LR; Endurance
Dyform DSC 8; etc.
Compacted Rope: Rope which is subjected to a compacting process
after closing, thus reducing its diameter.
Plastic (Solid Polymer) Filled Rope: Rope in which the free
internal spaces are filled with a solid polymer. The polymer extends to,
or slightly beyond, the outer circumference of the rope.
Cushioned Rope: Stranded rope in which the inner layers, inner
strands or core strands are covered with solid polymers or fibers to form
a cushion between adjacent strands or layers of strands.
Cushion Core Rope: Stranded rope in which the core is covered
(coated) or filled and covered (coated) with a solid polymer.
Solid Polymer Covered Rope: Rope which is covered (coated)
with a solid ploymer.
Solid Polymer Covered and Filled Rope: Rope which is covered
(coated) and filled with a solid polymer.
Rope Grade (Rr): A number corresponding to a wire tensile
strength grade on which the minimum breaking force of a rope is calculated.
Note: It does not imply that the actual tensile strength grades of the
wires in a rope are necessarily the same as the rope grade.
Preformed Rope: Stranded rope in which the wires in the strands
and the strands in the rope have their internal stresses reduced resulting
in a rope in which, after removal of any serving, the wires and the strands
will not spring out of the rope formation.
Note: Rotation Resistant stranded ropes should be regarded as non-preformed
rope even though the strands may have been partially (lightly) preformed
during the closing process.
Rope Class: A grouping of rope constructions where the number
of outer strands and the number of wires and how they are laid up are within
defined limits, resulting in ropes within the class having similar strength
and rotational properties.
Rope Construction: System which denotes the arrangement of
the strands and wires within a rope, e.g. 6x19S; 6x36WS; 18x7; 34x7. Cable-laid Rope: An assembly of several (usually six) single
layer stranded ropes (referred to as unit ropes) laid helically over a core
(usually a seventh single layer stranded rope).
Braided Rope: An assembly of several round strands braided
in pairs.
Electro-mechanical Rope: A stranded or spiral rope containing
electrical conductors.
Strand and Rope Lays
Lay
direction of strand:
The direction right (z) or left (s) corresponding to the direction of lay
of the outer layer of wires in relation to the longitudinal axis of the
strand.
Lay direction of rope: The direction right (Z) or left (S)
corresponding to the direction of lay of the outer strands in relation to
the longitudinal axis of a stranded rope or the direction of lay of the
outer wires in relation to the longitudinal axis of a spiral rope.
Regular lay: Stranded rope in which the direction of lay of
the wires in the outer strands is in the opposite direction to the lay of
the outer strands in the rope. Right Regular Lay is designated zZ and Left
Regular Lay is designated zS.
Note: This type of lay is sometimes referred to as 'ordinary' lay.
Lang lay: Stranded rope in which the direction of lay of the
wires in the outer strands is the same as that of the outer strands in the
rope. Right Lang Lay is designated zZ and Left Lang lay is designated sS.
Alternate lay: Stranded rope in which the lay of the outer
strands is alternatively Langšs lay and regular lay. Right hand alternate
lay is designated AZ and left hand alternate lay is designated AS.
Contra-lay: Rope in which at least one layer of wires in a
spiral rope or one layer of strands in a stranded rope is laid in the opposite
direction to the other layer(s) of wires or strands respectively.
Note: Contra-lay is only possible in spiral ropes having more than one
layer of wires and in multi-layer stranded ropes.
Rope lay length (Stranded Rope): That distance parallel to
the axis of the rope in which the outer strands make one complete turn (or
helix) about the axis of the rope.
Cores
Core:
Central element, usually of fiber or steel, of a single layer stranded rope,
around which are laid helically the outer strands of a stranded rope or
the outer unit ropes of a cable-laid rope.
Fibre core: Core made from either natural (e.g. hemp, sisal)
or synthetic fibres (e.g. polypropylene) and designated by its diameter
and runnage.
Steel core: Core produced either as an independent wire rope
(e.g. 7x7) or wire strand (e.g. 1x7).
Solid polymer core: Core produced as a single element of solid
polymer having a round or grooved shape. It may also contain internal elements
of wire or fibre.
Insert: Element of fibre or solid polymer so positioned as
to separate adjacent strands or wires in the same or overlying layers and
fill, or partly fill, some of the interstices in the rope.
Rope Characteristics and Properties
Fill factor: The ratio between the sum of the nominal cross-sectional
areas of all the load bearing wires in the rope and the circumscribed area
of the rope based on its nominal diameter.
Spinning loss factor: The ratio between the calculated minimum
breaking force of the rope and the calculated minimum aggregate breaking
force of the rope.
Minimum breaking force (Fmin):
Specified value, in tons or kN, below which the measured breaking force
is not allowed to fall in a prescribed test.
Rope torque: Value, usually expressed in ft pounds or N.m,
resulting from either test or calculation, relating to the torque generated
when both ends of the rope are fixed and the rope is subjected to tensile
loading.
Rope turn: Value, usually expressed in degrees per foot/meter,
resulting from either test or calculation, relating to the amount of rotation
when one end of the rope is free to rotate and the rope is subjected to
tensile loading.
Initial extension: Amount of extension which is attributed
to the initial bedding down of the wires within the strands and the strands
within the rope due to tensile loading.
Note: This is sometimes referred to as constructional stretch.
Elastic extension: Amount of extension which follows Hookes
Law within certain limits due to application of a tensile load.