Manitowoc National Crane NBT40 Series, Service Manual

Page: 35 / 220

National Crane
Published 8-01-2017 Control # 287-11
1-25
NBT40 SERVICE MANUAL INTRODUCTION
1
10
- 1/32 inch for diameters 3/8 and 1/2 inch inclusive.
- 3/64 inch for diameters 9/16 to 3/4 inch inclusive.
- 1/16 inch for diameters 7/8 to 1 1/8 inches inclusive.
- 3/32 inch for diameters 1/14 to 1 1/2 inches
inclusive.
• In standing ropes, more than two broken wires in one lay
in sections beyond end connections or more than one
broken wire at an end connection.
• National recommends that for cable extended booms, a
single damaged wire rope assembly shall require
replacement of the complete set of extension cables.
• National recommends that boom extension cables be
replaced every seven (7) years.
Seizing Wire Rope
It is important to seize the ends of rotation resistant wire
ropes to prevent the displacement and unraveling of the
individual wires and strands at the ends. All preformed and
non-preformed styles of wire rope need to be seized prior to
cutting. Seizings must be placed on both sides of the point
where the wire rope is to be cut. The two methods for seizing
wire ropes are described below.
Method 1
Using a length of soft annealed wire, place one end in the
groove between two strands of the wire rope. Turn the long
end of the annealed wire at right angles to the wire and wrap
it tightly over the portion in the groove.
The two ends of the annealed wire should be twisted
together tightly. Cut off the excess wire and pound the twist
flat against the wire rope (Figure 1-7).
Method 2
Wind a length of soft annealed wire around the wire rope at
least seven times. Twist the two ends together in the center
of the seizing. Tighten the seizing by alternately prying and
twisting. Cut off both ends of the wire and pound the twist flat
against the rope (Figure 1-8).
NOTE: Non-preformed wire rope should have two seizings
located on each side of the cut (Figure 1-9).
FIGURE 1-7
FIGURE 1-8
FIGURE 1-9
PREFORMED
NON-PREFORMED
Before Cutting
After Cutting
Before Cutting
After Cutting
6 Rope
Reference Only