Grove Published 11-22-2016, Control # 345-12 4-3
RT9130E-2 SERVICE MANUAL BOOM
Boom Retraction
The upper telescope cylinder retracts the outer-mid and two
retract cables pull the fly section in at the same time. When
the upper cylinder is fully retracted, the check valve for the
lower telescope cylinder is opened and the lower cylinder
starts to retract. The check valve for the upper cylinder is
closed as the lower cylinder starts to retract. The outer mid
and fly retract first and then the center mid and lastly the
inner mid.
RATED CAPACITY LIMITER (RCL) SYSTEM
(WITH BOOM CONTROL SYSTEM)
General
The crane has a 5-section sequence synchronized boom
assembly. The electronic control system interfaces with the
actuating systems, and provides the necessary controls,
according to the following system standards.
Telescoping Control System Description
Boom Configuration
The boom is a five section configuration (i.e. one fixed
section and four telescoping sections). The fully retracted
length of the boom is 42 ft (12.8 m) and the fully extended
length is 159.33 ft (48.5 m). The full extension value of all
four telescoping sections is the same (i.e., 159.33 ft - 42 ft/4
= 29.33 ft [48.564 m - 12,805 m/4 = 8.940 m]).
Extension/Retraction Modes
The boom telescoping system operates in either of two
modes selected by the operator, Automatic or Manual.
a. In Automatic mode, a single telescope controller
extends or retracts the boom at the correct speeds,
in the correct sequence of section movements, with
no action by the operator other than to actuate the
controller and to cease actuating it when the desired
boom length is achieved. The system also
automatically enforces a “soft” transition at each
section changeover point in the sequence, resulting
in smooth changes from section to section without
the need for the operator to “feather” the telescope
control.
b. In Manual mode, the operator has the selective
capability to adjust the extension of the inner mid
and center mid sections independently. Manual
mode adjustment is utilized only to reconfigure the
boom sections into a synchronized relationship
according to the programmed criteria for automatic
mode operation (if the boom has for any reason
become unsynchronized during operation in the
Automatic mode), or to extend the boom
intentionally in non-synchronized mode, so that
access holes in the boom sections align, and
serviceable internal components of the boom are
made accessible for maintenance. To prevent
overloading of the boom while the sections are
unsynchronized, when the Manual mode has been
selected, the RCL electronic controller limits the
allowable gross load to 22,046 lb (10,000kg) or 50%
of the load chart allowable capacity at the applicable
measured boom length, whichever figure is less. In
the Manual mode, the smoothness of the
changeover from section to section is entirely under
the control of the operator.
Extension/Retraction Sequence (Automatic
Mode)
Boom extension in the Automatic mode does not follow the
customary sequence whereby all the boom sections are
extended by the same proportion for any given boom length.
Instead, in order to optimize the crane structural and/or
stability limitations, the sections extend in particular
proportions according to the following sequences (as
directed by the particular load chart/crane configuration
selected by the operator; i.e. these sequences reside in the
system data software, not in the control software):
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