Retract Cable Adjustment; Telescope Circuit; Description; Theory Of Operation - Manitowoc Grove RT530E-2 Service And Maintenance Manual

RT530E-2 SERVICE MANUAL
4. Fully extend the boom and then retract it approximately
15 cm (6 in). This will create the loosest condition for
synchronizing and extension cables. Adjust the two
extend synchronizing cables at the top rear of the base
section. Adjust until 9 cm (3.5 in) of threaded cable end
is exposed and lock with jam nuts.
5. To adjust the five fly extend cables, fully retract the boom
to have access to the two extend cable sled adjusting
bolts at the back of the inner mid section through the
rear of the base section. Adjust these bolts to have 5 cm
(23 in) of bolt thread exposed from the sled.
6. Check through the side access holes in the boom, that
the fly extension cables have approximately 12 mm (0.5
in) slack and lock with jam nuts.

Retract Cable Adjustment

1. Extend each boom section approximately 900 mm (35.4
inches).
2. Adjust the outer mid retract cables at the front of the
base section to have approximately 65 mm (2.5 inches)
of threaded cable end exposed from the retract cable
mounting plate.
3. Adjust the fly retract cables at the front of the inner mid
section to have approximately 76 mm (2.9 inches) of
threaded cable exposed from the retract cable anchor
plate.
4. Fully retract the boom. All sections should bottom out on
the next inner section at the same time.
5. If one or more sections do not fully retract, tighten the
adjusting nut of the retraction cables for the section until
the section bottoms out. Repeat until al sections bottom
out at the same time.
6. Check through the side access holes in the boom, that
the tension is the same for all retract cables for a given
section. Lock all adjustments with jam nuts.

TELESCOPE CIRCUIT

Description

The boom telescope circuit consists of the telescope
hydraulic remote controller, telescope directional control
valve, holding valve, and the telescope cylinder.
GROVE
NOTE: If the crane is equipped with an auxiliary hoist, the
telescope function is controlled by a foot pedal
instead of a controller.
The telescope control valve is the closed spool type and is
described under VALVES in Section 8.
Refer to VALVES in Section 8 for a complete description of
the hydraulic remote controller.
The boom telescope cylinder is a two stage double acting,
rod ported cylinder. Foreign material is prevented from
entering the cylinder by a wiper seal during rod retraction. O-
ring seals prevent internal and external leakage. Refer to
CYLINDERS in Section 8 for a complete description of the
telescope cylinder.
The holding valve is threaded into a port block on the inner
rod end of the telescope cylinder. The holding valve
functions during the retraction, extension, or holding
operation. When holding the boom section at a given length,
oil is trapped in the cylinder by the holding valve. Refer to
VALVES in Section 8 for a complete description of the
holding valve.

Theory Of Operation

Flow from the pump travels to the telescope directional
control valve. Movement of the control lever for telescope
functions from neutral sends a pilot pressure signal to the
directional control valve to shift the spool in the directional
control valve. This aligns the appropriate passages in the
control valve to route oil to the telescope cylinder holding
valve. The holding valve, with its' internal make-up of valves
and springs, passes oil to and from the telescope cylinder.
During extension, oil unseats the poppet (check) valve in the
holding valve. This oil is routed to the piston sides of the
cylinder which forces the rods out of the cylinder, causing the
boom section to extend.
During retraction, oil enters the retract port and flows to the
rod sides of the cylinder. When pilot pressure reaches a pre-
determined value, the main poppet unseats, and oil flows
from the piston sides of the cylinder to the reservoir causing
the boom section to retract. All return flow from the
directional control valve goes to the reservoir.
Published 4-22-15, Control # 556-00
BOOM
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