Appendix E
ropes on even-part systems
(2,4,6,8
...
). In odd-part systems
(3,5,7,9
...
),
the measurement
of
"S"
is reduced
by
a factor below the next lowest even-part
system as shown in Table E5.
"D"
is the average pitch diameter (inches)
of
the
point and block sheaves, and
"d"
is the nominal wire rope diameter (inches).
TABLEE5
COMPUTING
"S"
2-Part System=Average Pitch Diameter
of
Point and Block Sheave
3-Part
System=2/3
of
2-Patt System
4-Part
System=Diagonal Distance
of
Rope Parts
5-Part System=4/5
of
4-Part System.
6-Part
System-Diagonal Distance
of
Rope Parts
7-Part System-617
of
6-Part System
In summary, the four variables, which can be established for a given condition,
are to be used to calculate the probability
of
cabling.
It
must be remembered that
this concept is based upon proper handling and reeving
of
the wire rope on the
machine. Any undue twist which
is
in the rope during operation will affect the
torsional properties
of
the line. Suggestions as to proper handling
of
the rope in
the field can be obtained from any wire rope producer. It should also be noted
that differences in rope manufacturing may be sufficient to yield variations in the
results. All lifts where cabling may occur should be approached with caution.
Wire Rope Technical Board - Wire Rope Users Manual, Fourth Edition
'143
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