Manitowoc Grove RT770E Service Maintenance Manual

5-1
RT770E HOIST AND COUNTERWEIGHT
5
Published 11/26/2014, Control # 447-05
GROVE
SECTION 5
HOIST AND COUNTERWEIGHT
SECTION CONTENTS
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Warm-up Procedure . . . . . . . . . . . . . . . . . . . . . . . 5-2
Hoist Area Access . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Functional Check . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Fluid Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Usage and Inspection . . . . . . . . . . . . . . . . . . . . . . 5-6
Preventative Maintenance . . . . . . . . . . . . . . . . . . 5-6
Oil Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Brake Test Procedure . . . . . . . . . . . . . . . . . . . . . . 5-8
Hoist To Boom Alignment . . . . . . . . . . . . . . . . . . . 5-9
Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Motor And Brake. . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Idler Drum And Cable Follower . . . . . . . . . . . . . . 5-12
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Third Wrap Indicator (Optional—Standard on
CE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Hoist Rotation Indicator (HRI) and Display
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Hoist Drum Rotation Indicator System . . . . . . . . 5-16
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Hoist Rotation Indicator (HRI) Display System . . 5-18
Hoist Control Valves . . . . . . . . . . . . . . . . . . . . . . . 5-19
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
Fixed Counterweight . . . . . . . . . . . . . . . . . . . . . . . 5-20
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Counterweight Plate . . . . . . . . . . . . . . . . . . . . . . 5-20
Removable Counterweight (Optional) . . . . . . . . . 5-22
Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
DESCRIPTION
One standard hoist is available for both the main and
auxiliary, the GHP30A Figure 5-2. The hoist incorporates
one dual displacement piston motor which drives a reduction
unit within the hoist. The hoist utilizes planetary reduction
with a multi-disc automatic brake that is spring applied and
hydraulically released. An overrunning clutch allows the
hoist to be raised without releasing the brake while at the
same time holding the load until there is sufficient pressure to
release the brake when hoisting down. The hoist motor
controls both speed and torque of the hoist.
There are two modes in which the hoist operates. One mode
is high speed. The pilot solenoid valve shifts the selector
spool on the motor to provide minimum motor displacement.
This gives high line speed and low torque.
The second mode is low speed. The pilot solenoid valve
shifts the selector spool on the motor to provide maximum
motor displacement. This gives low line speeds and high
torque.
THEORY OF OPERATION
Flow from section one of pump number one is routed through
the swivel to the directional control valve bank.
When the main hoist control lever in the cab is moved from
neutral, it sends a pilot pressure signal to the main hoist
directional control valve to shift the valve spool to route
hydraulic flow to the hoist motor control valve. The hoist
motor control valve internally routes the hydraulic flow to the
hoist motors in a series or parallel hydraulic circuit as
selected by the operator.
When the auxiliary hoist control lever in the cab is moved
from neutral, it sends a pilot pressure signal to the auxiliary
hoist directional control valve to shift the valve spool to route
hydraulic flow to the hoist motor control valve. The hoist
motor control valve internally routes the hydraulic flow to the
hoist motors in a series or parallel hydraulic circuit as
selected by the operator.
Additional flow (high speed boost) is obtained by using the
Hydraulic Boost Switch. Positioning the switch to HI allows

Manitowoc Grove RT770E Specifications

General

Brand	Manitowoc
Model	Grove RT770E
Category	Construction Equipment
Language	English