Jerr-Dan MPL-60, Руководство по эксплуатации и безопасности

Страница: 79 / 98

Section 6 - Maintenance
5376000278 6-9
Keep Wraps Tight
The end of the rope must be securely and evenly attached to the drum anchorage
point by the method recommended by the equipment manufacturer. At least
fi ve
wraps of wire rope must remain on the drum as dead wraps when the rope is unwound
during normal operations. Locate the dead end rope anchorage point on the drum
in relation to the direction of the lay of the rope. Do not use an anchorage point that
does not correspond with the rope lay. Mismatching rope lay and anchorage point will
cause the wraps to spread apart from each other and allow the rope to cross over on
the drum. Very gappy winding will occur resulting in crushing damage in multilayer
applications.
Back tension must be continually applied to the payout reel and the crewman
installing the rope must proceed at a slow and steady pace whether the drum is
smooth or grooved. Regardless of the bene
fi ts of a grooved drum, tension must be
applied to ensure proper spooling. An improperly installed rope on a grooved drum
will wear just as quickly as an improperly installed rope on a smooth drum. If a wire
rope is poorly wound and as a result jumps the grooves, it will be crushed and cut
under operating load conditions where it crosses the grooves.
Every wrap on the fi rst or foundation layer must be installed very tightly and be
without gaps. Careless winding results in poor spooling and will eventually lead
to short service life. The following layers of rope must lay in the grooves formed
between adjacent turns of the preceding layer of rope. If any type of overwind or
crosswinding occurs at this stage of installation and is not corrected immediately,
poor spooling and crushing damage will occur.
On a multilayer spooling drum be sure that the last layer remains at least two rope
diameters below the drum
fl ange top. Do not use a longer length than is required
because the excess wire rope will cause unnecessary crushing and may jump the
fl ange. Loose wraps that occur at any time must be corrected immediately to prevent
catastrophic rope failure.
The use of a mallet is acceptable to ensure tight wraps, however a steel-faced mallet
should be covered with plastic or rubber to prevent damage to the rope wires and
strands.