National Crane 1-21-2019 Control # 104-07 1-21
1400A SERVICE MANUAL INTRODUCTION
WIRE ROPE
General
The following information includes inspection, replacement,
and maintenance guidelines for wire rope as established by
ANSI/ASME B30.5, federal regulations, and National Crane
specifications. The inspection interval shall be determined by
a qualified person and shall be based on expected rope life
as determined by experience, severity of environment,
percentage of capacity lifts, frequency 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 information contains inspection
and maintenance procedures for wire ropes used on
National products as load lines, hoisting cables, boom
extension and retraction cables, pendant cables, and hook
block tie down cables.
Environmental Conditions
The life expectancy of wire rope may vary due to the degree
of environmental hostility. Variation in temperature,
continuous excessive moisture levels, exposure to corrosive
chemicals or vapors, or subjecting the wire rope to abrasive
material can shorten wire rope life. Frequent inspections and
maintenance of the wire rope is recommended for preventing
premature wear and to insure long-term performance.
Dynamic Shock Loads
Subjecting wire rope to abnormal loads shortens the ropes
life expectancy. Examples of this type of loading are as
follows:
• High velocity movement followed by abrupt stops
(hoisting or swinging of a load).
• Suspending loads while traveling over irregular surfaces
such as railroad tracks, potholes, and rough terrain.
• Moving a load that is beyond the cranes rated capacity.
TW =
Ta x L
L + A
Ta x L
L - A
or
Ta = Torque required (specified)
TW = Wrench scale reading or limit setting of
torque wrench
L = Length of torque wrench in inches (center of drive
tang to handle pivot pin or center of hand grip
extension handles are considered part of wrench
length, when used).
A = Length of adapter extensions in inches
Fo
r
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