Manitowoc Grove RT770E, Service Maintenance Manual

Page: 220 / 357

5-20 Published 11/26/2014, Control # 447-05
HOIST AND COUNTERWEIGHT RT770E
FIXED COUNTERWEIGHT
Description
The counterweight Figure 5-14 is pinned to the rear of the
superstructure and weighs about 6540 kg (14,400 lb). For
cranes without an auxiliary hoist, an additional 672 kg
(1478 lb) counterweight is bolted to the hoist mounting area
instead of the auxiliary hoist.
Maintenance
Removal
1. Fully extend and set the outriggers.
2. Rotate the superstructure so the counterweight is over
the front of the carrier to gain additional clearance.
NOTE: The counterweight weighs approximately 6540 kg
(14,400 lb).
3. Lower and fully retract the boom.
NOTE: Use of a forklift to install or remove the
counterweight is not recommended. Damage or
misalignment of the counterweight can result if a
forklift is used for installation or removal.
4. Attach an adequate lifting device to the counterweight.
5. Adjust the four counterweight leveling bolts to provide
maximum clearance of the counterweight from the
superstructure.
6. Take up any slack on the lifting device and raise the
counterweight just enough to remove any pressure on
the left and right counterweight pin assemblies.
7. Remove the pins from the superstructure frame lugs and
the counterweight. To remove each pin, push pin in and
turn it so its roll pin disengages from the related catch on
the counterweight.
8. Lower the counterweight enough to clear the
superstructure. Remove the counterweight from the
crane and replace the retainer pins in mounting lugs.
9. Rotate the superstructure to the normal travel position.
Installation
1. Fully extend and set the outriggers.
2. Rotate the superstructure so the counterweight will be
over the front of the carrier to gain additional clearance.
NOTE: The counterweight weighs approximately 6540 kg
(14,400 lb).
U s e o f a f o r k l i ft t o i n s t a l l o r r e m o v e t h e
counterweight is not recommended; damage or
misalignment of the counterweight can result.
3. Attach an adequate lifting device to the counterweight
and lift the counterweight into place on the
superstructure, aligning the mounting holes on the
counterweight to the holes in the superstructure.
4. Secure the counterweight to the superstructure with the
two pins. Secure the pin by pushing it in and turning it so
the roll pin engages the related catch on the
counterweight. Release the pin so its spring can hold the
pin in place.
5. Remove the lifting device from the counterweight.
6. Using the four counterweight leveling bolts, level the
counterweight and eliminate any relative movement
between the counterweight and turntable. Maximum
height of counterweight shall not exceed 6 mm (0.24 in)
out of level with the turntable bearing when measured
from either counterweight outer edge.
Counterweight Plate
The counterweight has a removable counterweight plate
attached to its rear wall with capscrews, flat washers and
nuts. This plate weighs 395 kg (870 lb). Use appropriate
caution and safety equipment in removing and installing this
plate.
DANGER
Crushing Hazard!
Death or serious injury could result from being crushed by
a falling counterweight.
Ensure the counterweight pin assemblies are installed
properly and are secure in their catches.
When lifting/handling the counterweight, keep the chains/
straps vertical to minimize side pull on the lifting lugs.
CAUTION
When lifting/handling the counterweight, keep the chains/
straps vertical to minimize side pull on the lifting lugs