Manitowoc Grove RT770E, Руководство по техническому обслуживанию

Страница: 34 / 357

INTRODUCTION RT770E SERVICE MANUAL
1-20 Published 11/26/2014, Control # 447-05
WIRE ROPE
General
The following compendium of information is from various
wire rope manufacturers and includes inspection,
replacement, and maintenance guidelines for wire rope as
established by ANSI/ASME B30.5, federal regulations, and
Manitowoc. The inspection interval shall be determined by a
qualified person and shall be based on such factors as
expected rope life as determined by experience on the
particular installation or similar installations, severity of
environment, percentage of capacity lifts, frequency rates of
operation, and exposure to shock loads. Periodic
Inspections need not be at equal calendar intervals and
should be performed at shorter time intervals as the wire
rope approaches the end of its useful life. A periodic
inspection shall be performed at least once a year. The
following provides inspection and maintenance procedures
for wire ropes used on Grove products (e.g. wire rope used
as load lines [hoisting cables], boom extension and
retraction cables, pendant cables, tow winch cables, and
hook block tie down cables).
Environmental Conditions
The life expectancy of wire rope may vary due to the degree
of environmental hostility and other conditions to which these
mechanical devices are subjected. Variation in temperature,
continuous excessive moisture levels, exposure to corrosive
chemicals or vapors or subjecting the wire rope to abrasive
material may shorten normal wire rope life. Frequent/
periodic inspections and maintenance of your wire rope is
recommended for preventing premature wear and to insure
long-term satisfactory performance.
Dynamic Shock Loads
Subjecting wire rope to abnormal loads beyond the
endurance limit will shorten the wire ropes life expectancy.
Examples of this type of loading are listed below.
1. High velocity movement e.g.; hoisting or swinging of a
load followed by abrupt stops.
2. Suspending loads while traveling over irregular surfaces
such as railroad tracks, potholes, and rough terrain.
3. Moving a load that is beyond the rated capacity of the
lifting mechanism, i.e.; overloading.
Lubrication
A wire rope cannot be lubricated sufficiently during
manufacture to last it’s entire life. Therefore, new lubricant
must be added throughout the life of a rope to replace factory
lubricant which is used or lost. It is important that lubricant
applied as part of a maintenance program shall be
compatible with the original lubricant, and to this end, the
rope manufacturer should be consulted. Lubricant applied
shall be of the type which does not hinder visual inspection.
Those sections of rope which are located over sheaves or
otherwise hidden during inspection and maintenance
procedures require special attention when lubricating rope.
The object of rope lubrication is to reduce internal friction and
to prevent corrosion.
During fabrication, ropes receive lubrication; the kind and
amount depends on the rope’s size, type, and anticipated
use. This in-process treatment will provide the finished rope
with ample protection for a reasonable time if it is stored
under proper conditions. But, when the rope is put into
service, the initial lubrication may be less than needed for the
full useful life of the rope. Because of this possibility, periodic
applications of a suitable rope lubricant are necessary.
The following are important characteristics of a good wire
rope lubricant:
• It should be free from acids and alkalis.
• It should have sufficient adhesive strength to remain on
the rope.
• It should be of a viscosity capable of penetrating the
interstices between wires and strands.
• It should not be soluble in the medium surrounding it
under the actual operating conditions (i.e. water).
• It should have a high film strength.
• It should resist oxidation.
Before applying lubrication, accumulations of dirt or other
abrasive material should be removed from the rope.
Cleaning can be accomplished by using a stiff wire brush and
solvent, compressed air, or live steam. Immediately after the
wire rope is cleaned, it should be lubricated. Many
techniques may be used; these include bath, dripping,
pouring, swabbing, painting or pressure spray methods.
Whenever possible, the lubricant should be applied at the
top of a bend in the rope, because at that point the strands
are spread by bending and are more easily penetrated.
There should be no load on the rope while it is being
lubricated. It should be noted, the service life of wire rope will
be directly proportional to the effectiveness of the method
used and amount of lubricant reaching the working parts of
the rope.
Precautions and Recommendations During
Inspection or Replacement
1. Always lock out equipment power when removing or
installing wire rope assemblies.
2. Always use safety glasses for eye protection.
3. Wear protective clothing, gloves, and safety shoes as
appropriate.
4. Use supports and clamps to prevent uncontrolled
movement of wire rope, parts, and equipment.