Operator`s manual

Figure 4-11 is a composite illustration showing the complete ladder cable layout. The numbers in the
square boxes indicate to which ladder sections the cables or pulleys are attached. This illustration is
broken down into groups to support the descriptions in the text that follows. The arrow with a numbered
box indicates direction of ladder section movement.
NOTE: Ladder extension is controlled by pairs of cables and, in the event one extension cable is broken,
the ladder can be extended by means of the remaining one.
4.2.2 Ladder Extension
The ladder extension cables are wound on the top-side (anti-clockwise) of each of the two winch drums
(see Figure 4-12, numbers 1 and 8). They pass around the two vertical pulleys mounted on the forward
end of Section 1 (4) and (5) and then around the double sheaves mounted horizontally to Section 2 (2)
and (7). Finally, they are fastened to the forward end of the left and right underside of Section 1, (3) and
(6).
When the winch drums are rotated anti-clockwise by the hydraulic motor, the extension cables are wound
onto the drums causing Section 2 to extend as the cables shorten. When Section 2 extends, it causes
Section 3 to extend at the same rate through the action of the cables shown at Figure 4-13.
As Section 2 moves away from the winch, the canted sheaves mounted on Section 2 (3) and (4) push on
the cables connected to Section 1 (1) and (6) and cause Section 3 to move with Section 2.
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