Manitowoc Grove RT770E, Service Maintenance Manual

Page: 189 / 357

4-45 Published 11/26/2014, Control # 447-05
RT770E SERVICE MANUAL BOOM
4
GROVE
BI-FOLD BOOM EXTENSION
Description
A 33 ft (10.1 m) fixed offsetable or a 10.1 to 17.1 m (33 to 56
ft) folding offsetable swingaway boom extension is provided
to obtain additional boom reach.
The boom extension mounts directly to the boom nose
utilizing a four point attachment. In addition, the swingaway
can be stowed on the right side of the boom base section.
Removing the attach pins from the attach points on the left
side of the boom nose allows the swingaway to be rotated
and stowed on the right side of the boom base section.
The fixed swingaway weighs approximately 1706 lb (774 kg)
and the folding swingaway weighs approximately 2430 lb
(1102 kg).
Boom Extension Rigging Mode
This crane is equipped with a boom control system that
enters a Boom Extension Rigging Mode when the boom stop
block is disengaged and a minimum boom length is
detected. While in the Boom Extension Rigging Mode the
crane will not allow the following movements:
• Extension of the boom in Auto Mode, with A Mode
selected
• Extension of the boom in Manual Mode, with Boom
Section 2-4 selected
The Boom Extension Rigging Mode requires that the boom
be extended in Auto Mode with B Mode selected, or Manual
Mode with Section 1 selected until the boom automatically
stops and is clear of the guide ramps and stowage pins on
the front and rear stowage brackets.
To exit the Boom Extension Rigging Mode the boom must be
fully retracted causing the section 1 and section 2 proximity
switches to be activated. Upon exiting the Boom Extension
Rigging Mode, restrictions of boom operating modes are
removed.
Erecting the Boom Extension
1. Fully extend and set the outriggers.
2. Position the boom over the front.
3. Set the boom manual/automatic mode selector switch to
the AUTO position.
4. Set the boom A/B mode selector switch to the B mode.
5. If extended, fully retract all the boom sections and lower
the boom to minimum elevation to permit ease of
installation of pins and access to the boom nose.
NOTE: The auxiliary boom nose (rooster sheave) does not
have to be removed. However, if reeved, the hoist
cable must be removed from the sheave.
6. Rig either the main hoist or optional auxiliary hoist cable
for single part line with nothing but the wedge socket on
the end of the cable.
7. Extend the boom enough to disengage the spring
loaded boom stop block (Figure 4-61).
DANGER
Before attempting to erect or stow the boom extension;
read and strictly adhere to all danger decals installed on
the boom/boom nose, boom extension, and stowage
brackets.
Lifting over the bi-fold extension base section is strictly
prohibited, when the fly extension is either erected or
folded along side of extension base section.
DANGER
Extending boom sections 2 through 4 during the erection
or stowage of the boom extension could permit
disengagement of the anti-roll guides, allowing an
uncontrolled movement of the extension, resulting in
death, personal injury, or property damage.
Always ensure the crane is in the B mode during erection
or stowage of the boom extension. Never erect or stow
the boom extension in the recovery mode.
FIGURE 4-61
7921-1