SETUP AND INSTALLATION 999 LUFFING JIB OPERATOR MANUAL
4-28
Published 05-15-17, Control # 043-09
11. Retract and store jib stop struts. Perform Final Lowering
Procedure.
12. Struts can now be lowered. See Lowering Struts in this
section for procedure.
Final Lowering Procedure
Perform the following steps once the boom and jib have
been lowered to either of the following positions:
IN-LINE PROCEDURE — jib point rollers just contact
ground.
JACK-KNIFE PROCEDURE — jib stop pendants just start to
go into tension (approximately 168° boom to jib angle).
1. Disengage jib stop strut pins with hand winch on left side
of jib top.
NOTE: Outer end of jib stop strut pins are painted white (or
other contrasting color) to make pins more visible
from ground.
2. Slowly lower boom to retract jib stop inner strut.
It will be necessary to use limit bypass switch to boom
down if BLOCK UP or MAX UP limits are on.
3. Stop lowering boom when jib stop inner strut is fully
retracted (Figure 4-10
, View B).
4. Remove both quick-release pins from storage holes and
install pins to connect jib stop inner strut to outer strut in
retracted position (Figure 4-10
, View B).
5. Unpin both jib stop pendants from jib stop inner strut
(Figure 4-10
, View B).
6. Rotate jib stop struts to rear and pin struts in stored
position under boom top (Figure 4-3
, View B).
7. Lower boom onto blocking placed under connectors
between boom top and insert next to boom top. Size
height of blocking so distance between boom point
sheaves and ground is approximately 26 in (0,7 mm)
(Figure 4-3
, View B).
8. Lower struts if required.
Lowering Struts
1. Luff down to lower jib strut until storage holes in strut line
up with holes in strut supports (10, Figure 4-8
, View G).
2. Pin jib strut to strut support as shown in (Figure 4-8
,
View G).
3. Remove quick-release pins (4, Figure 4-8
, View E) from
storage holes in main strut stop tubes and install both
quick-release pins in erecting holes (View D). It may be
necessary to luff up or down slightly to align holes.
4. Remove both stop pins (5, Figure 4-8
, View E). It may be
necessary to luff up or down slightly to loosen pins.
5. Pay out luffing hoist wire rope to lower main strut until
holes in middle stop tubes (7, Figure 4-8
, View B) line up
with bottom holes in lower stop tubes (6).
6. Install stop pins (5, Figure 4-8
, View B) to connect
middle stop tubes to lower stop tubes.
7. Unpin main strut pendants (1, Figure 4-8
, View C) from
basic backstay pendants (2) on boom top.
8. Remove load block or weight ball from front drum load
line (if attached).
9. Route front drum load line over top of left-upper guide
sheave in wire rope guide on boom butt (Figure 4-6
,
View C).
10. Attach wedge socket (10, Figure 4-7
, View A) to front
drum load line.
11. Unpin strut handling pendant and link (7, Figure 4-7
,
View C) from bracket on left side main strut pendant.
CAUTION
Jib Stop Damage!
Once jib stop pendants start to go into tension, do not
lower boom any farther until jack-knife lowering step 11
is
performed. Damage to jib stop struts or pendants will
result if struts are over tensioned.
WARNING
Moving Part Hazard!
Do not stand on boom top or jib butt while main strut is
being raised or lowered.
Wait until main strut is stopped and supported by load line
or luffing hoist wire rope before climbing onto boom top or
jib butt when connecting and disconnecting strut stop
tubes.
WARNING
Falling Load Hazard!
Do not perform step 4 until main strut is supported by
luffing hoist wire rope.
Strut stop tubes will retract and main strut will fall
suddenly with violent force.
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