Non Rotating Wire Rope Aulone
provide a variety of anti-spin non rotating wire rope (also called
rotation resistant wire-rope). All standard wire-rope has a tendency to
develop torque and therefore prone to rotation.
Non-rotating
wire ropes are designed so that the wire-rope outer rotational force
naturally counteracts the inner strands rotational force in the event
that a rope is subjected to a load.
Various classes of non-rotating wire rope are available such as 35WX7,35WXK7 18×7 and 19×7. discuss your
application and we can advise on a great anti-spin wire-rope solution
for you.
Why use Non Rotating Wire Rope When
a load or force is attached to a standard rope the forces will cause
the rope to elongate and rotate, therefore spin the load, quite possible
out of control, this can be a dangerous practice, especially for heavy
loads and loads lifted from a great height such as on a crane. When the
rope rotates in this way the strands will begin to unravel, loosing
strength and the rope will undoubtedly fail, this could be catastrophic.
It is for these reasons that non rotating rope is commonly used for
many types of lifting applications including main hoist rope, whip rope,
crane rope, off-shore and deck rope and more.
Characteristics Non
rotating wire rope or rotation resistant wire rope has a different
construction to standard wire rope. Rather than all wires and strands
being laid in the same direction, a rotation resistant wire rope
consists of inner strands being laid in the opposite direction to the
outer layers, for example the inner may be constructed in left hand lay
whilst the outer layer is in right hand lay. The nature of this
construction means that torsional forces on the inner and outer
wires/strands will counteract each other and so minimise the risk of
unravelling.
It
is worth noting that the number of strand layers will have an effect of
the resistance of rotation. A 2 layer rope has less resistance than a 3
layer rope, therefore the more layers the rope has the greater rotation
resistance it will have.
non rotating wire rope
These
types of ropes can be classified as spin resistant, rotation resistant
or non rotation resistant; they are classed on the basis of the number
of rotations a certain length of rope does when a force of 20% of the
MBF is applied; with 1 turn or less the rope will be classified as non
rotating; with rotations between 1 & 4 the rope is classed as low
rotation and for rotations between 4 & 10 the rope will be
classified as spin resistant, any higher and the rope is not rotation
resistant at all.
Care & Handling of Rotation Resistant Wire Rope Non rotating or rotation resistant ropes need to be used and handled with care, they are often deemed to be less
stable than conventional wire ropes, this is due to the friction on the
inner wires caused by the strand cross over’s which will eventually
cause the inner wires to break up, this is more apparent on non rotating
wire rope with two layers. Ropes with 3 or more strand layers will
distribute the radial pressures more evenly, and reduce friction and
stress on the inner wires.
Regular,
thorough inspections of non rotating rope are essential due to the fact
that it is the inner strands that often break first and broken internal
wires often go unnoticed as they are difficult to see. Rope Services
Direct offer inspections on all rope with certification issued on
completion.
Shock
loading should be avoided with rotation resistant wire rope as this can
cause rope distortions, bird caging and core protrusion where the inner
strands/core extend out from the outer layer.
Both
ends of the rope should be seized correctly to prevent the strands from
unwinding. Any end fittings should be carefully fitted to prevent
damage to the rope such as kinking and unravelling; they can also have
an effect on the rotational balance if not fitted correctly. Aulone can supply non rotating wire rope to your specifications at the most reasonable prices .