Manitowoc Published 05-15-17, Control # 043-09 4-25
999 LUFFING JIB OPERATOR MANUAL SETUP AND INSTALLATION
Lowering Boom and Jib
As defined in the raising procedure chart, one of two
methods can be used to lower the boom and jib depending
on the boom and jib combination: IN-LINE METHOD or
JACK-KNIFE METHOD.
See the Luffing Jib Raising Procedure to determine which
method can be used.
In-Line Lowering Procedure
See Figure 4-13 for the following procedure. Circled
numbers in Figure 4-13
correspond to numbered steps in
following procedure.
NOTE: It is normal for the following for BLOCK UP, MAX
UP 1, and MAX UP 2 limits to come on during the
lowering procedure.
1. Swing upperworks in-line with lowerworks so boom is
centered over either end of crawlers.
2. Travel crawler rollers onto blocking (end under boom).
3. Swing boom and jib slightly to either side of center and
lower load blocks and/or weight balls onto ground. Then
swing boom and jib in-line with crawlers.
4. Raise jib to 168° boom to jib angle. Monitor this angle
on digital display.
5. Slowly boom down to lower boom and jib until jib point
rollers contact ground. It will be necessary to use limit
bypass switch if BLOCK UP limit is on.
6. Haul in load lines as boom and jib are lowered, but do
not lift load blocks or weight balls off ground.
7. Retract and store jib stop struts. Perform Final Lowering
Procedure.
8. Struts can now be lowered. See Lowering Struts later in
this section for procedure.
WARNING
Falling Boom And Jib Hazard!
Select and confirm LUFFING JIB mode. Operating in any
other mode with luffing jib attached is prohibited.
Luffing jib limits are disabled when LUFFING JIB mode is
off. Boom and jib could be pulled over backwards.
DANGER
Moving Part Hazard!
Warn all personnel to stand clear of jib point rollers while
lowering boom and jib.
Death or severe crushing injuries will occur if personnel
come into contact with rollers.
DANGER
Tipping Crane Hazard!
Lower all boom and jib combinations over blocked
crawlers, otherwise crane will tip.
WARNING
Tipping Crane Hazard!
Lower all load blocks and/or weight balls onto ground
before lowering boom and jib. Crane could tip if this step
is not performed.
DANGER
Tipping Crane Hazard!
For in-line method, do not lower boom and jib
combinations longer than specified in Raising Procedure
Chart. Crane will tip.
CAUTION
Jib Stop Damage!
Do not lower boom any farther until in-line lowering step 7
is performed. Once jib point rollers contact ground,
damage to jib stop struts or pendants will result if struts
are over tensioned
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