Oshkosh Corporation JERR-DAN 20NGADF6T-LP, Operation And Safety Manual

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Section 6 - Maintenance
5376000207 6-7
6.5 WIRE ROPE INSTALLATION
Proper Unreeling Procedures
Wire rope can be permanently damaged by improper unreeling or uncoiling practices.
The majority of wire rope performance problems start here. Improper unreeling
practices lead to premature rope replacement, hoisting problems and rope failure.
Place the payout reel as far away from the boom tip as is practical, moving away from
the chassis. Never place the payout reel closer to the chassis than the boom point
sheave. Doing so may introduce a reverse bend into the rope and cause spooling
problems. Take care to determine whether the wire rope will wind over or under the
drum before proceeding.
Unreeling & Uncoiling and Kinks
• The Right Way To Unreel. To unreel wire rope from a heavy reel, place a shaft
through the center and jack up the reel far enough to clear the floor and revolve
easily. One person holds the end of the rope and walks a straight line away from
the reel, taking the wire rope off the top of the reel. A second person regulates the
speed of the turning reel by holding a wood block against the flange as a brake,
taking care to keep slack from developing on the reel, as this can easily cause a
kink in the rope. Lightweight reels can be properly unreeled using a vertical shaft;
the same care should be taken to keep the rope taut.
• The Wrong Way To Unreel.
If a reel of wire rope is laid on its flange with its axis
vertical to the floor and the rope unreeled by throwing off the turns, spirals will
occur and kinks are likely to form in the rope. Wire rope always should be handled
in a way that neither twists nor unlays it. If handled in a careless manner, reverse
bends and kinks can easily occur.
• The Right Way To Uncoil.
There is only one correct way to uncoil wire rope. One
person must hold the end of the rope while a second person rolls the coil along
the floor, backing away. The rope is allowed to uncoil naturally with the lay, without
spiralling or twisting. Always uncoil wire rope as shown.
• The Wrong Way To Uncoil. If a coil of wire rope is laid flat on the floor and
uncoiled by pulling it straight off, spirals will occur and kinking is likely. Torsions
are put into the rope by every loop that is pulled off, and the rope becomes twisted
and unmanageable. Also, wire rope cannot be uncoiled like hemp rope. Pulling
one end through the middle of the coil will only result in kinking.
• Kinks.
Great stress has been placed on the care that should be taken to avoid
kinks in wire rope. Kinks are places where the rope has been unintentionally bent
to a permanent set. This happens where loops are pulled through by tension on
the rope until the diameter of the loop is only a few inches. They are also caused
by bending a rope around a sheave having too severe a radius. Wires in the
strands at the kink are permanently damaged and will not give normal service,
even after apparent “restraightening.”