Manitowoc 999 Service And Maintenance Manual

Reference Only
Manitowoc Published 05-16-17, Control # 233-03 4-1
999 SERVICE/MAINTENANCE MANUAL BOOM
4
SECTION 4
BOOM
AUTOMATIC BOOM STOP
Maximum Boom Angle
Boom stop limit switch assembly (5, Figure 4-1)
automatically stops the boom and applies the boom hoist
brake when the boom is raised to Angle A.
Operation
See Figure 4-2 for the following description.
When the boom is below the maximum angle, limit switch (5)
is closed. The boom hoist can be operated.
When the boom is raised to the maximum angle, boom butt
(1) pushes adjusting rod (2a, 2b, or 2c) in and actuator rod
(11, View A) opens limit switch (5). Boom hoist operation
stops automatically because the open limit switch turns off
power to the boom hoist electric circuit. The boom hoist
pump shifts to neutral and the brake applies to stop boom
movement.
Maintenance
At least once weekly, check that the automatic boom stop
stops the boom at the specified maximum angle. If not,
replace any worn or damaged parts and/or adjust the boom
stop.
Once the automatic boom stop is properly adjusted, it should
not require periodic adjustment. Adjustment is required,
however, when:
• The luffing jib is installed or removed.
• Parts are replaced.
Table 4-1
WARNING
Falling Attachment Hazard!
If boom fails to stop for any reason, stop engine
immediately. Troubleshoot system to determine problem.
Do not resume operation until problem has been
corrected.
WARNING
Falling Attachment Hazard!
Do not operate crane unless automatic boom stop is
properly adjusted and operational. Do not adjust
maximum operating angle higher than specified. Boom
could be pulled over backwards or collapse, causing
death or serious injury.
Angle A Adjusting Rod — Length
81° — #82 Long Reach Boom 2a — 7 in (178 mm)
82° — #22E Open-Throat Top 2a — 7 in (178 mm)
83° — #82 or 22EL Heavy Lift Boom 2a — 7 in (178 mm)
83° — #22E Open-Throat Top Offset 4-1/2° 2a — 7 in (178 mm)
88° — #82 or 22EL Heavy Lift Boom with #135 or 149 Luffing Jib
when the boom up limit can be bypassed *
2b — 4-3/4 in (121 mm)
89° — #82 or 22EL Heavy Lift Boom with #135 or 149 Luffing Jib
when the boom up limit cannot be bypassed *
2c — 4-3/8 in (111 mm)
*
To determine if the boom up limit on your crane can be bypassed, perform Bypass Limit Test.

Manitowoc 999 Specifications

General

Brand	Manitowoc
Model	999
Category	Construction Equipment
Language	English