5-8
Published 9-04-2014, Control # 422-08
HOIST AND COUNTERWEIGHT
RT765E-2 SERVICE MANUAL
Replace any parts showing excessive wear and any spring
whose length is shorter than the minimum shown in the
applicable hoist Service Manual.
Reassemble the brake and hoist and repeat the above steps.
When testing is complete, reattach the brake release line to
the brake release port.
T h e fo l l o w i n g s h o u l d b e c ar r i e d o ut a l o ng w i t h t h e
instructions in
1.
Annually, have the hoist oil condition tested. This will
give advance warning of developing wear patterns. Any
signs of abnormal contamination should be treated
seriously and the internal components of the hoist
should be examined carefully, at the earliest opportunity.
2.
Annually, check for correct function of the hoist brake by
conducting a high line pull load test, ensuring the brake
holds without creeping and that the hoist control is
correct. The function of the hoist brake should be
checked more often if abnormal operating conditions or
characteristics exist.
3.
Every 10,000 hours or every ten years as part of a
preventative maintenance program, we recommend that
hoist assemblies be opened in a properly controlled
workshop environment. The major internal components
(gears, spline couplings, shafts, etc.) should be
examined for damage and/or wear. New components
should be installed if any are found to be worn or if there
is evidence of heat or other damage. Reassemble the
hoist using all new seals, bearings, fasteners, washers,
brake discs, brake stators, sprag clutch, and springs.
A comprehensive hoist line pull and load holding test must
be carried out following any such repair work.
Manitowoc Crane Care offers prepackaged kits that include
all the seals, bearings, fasteners, washers, brake disks,
brake stators, sprag clutch, and springs that are required for
reassembling the hoist after inspection. During the
inspection, if components not included in the kit are found to
be worn or damaged, contact your Manitowoc Cranes
distributor or Manitowoc Crane Care to order replacement.
HOIST TO BOOM ALIGNMENT
Preparation
Boom alignment must be completed before attempting hoist
alignment Figure 5-5. If the hoist is not properly aligned, the
cable can be damaged or fine control could be affected.
The crane must be set on outriggers fully extended and the
crane must be leveled. The boom must be over the front.
Tools Required
•
Two foot square
•
Mason cord
•
Chalk
•
Protractor
Procedure
The hoist mounting location will determine the alignment
procedure used. Shift one side of the hoist back or forward to
align the hoist with the boom sheave for cranes that have the
hoist mounted either directly to the boom or on a mount
attached to the boom. It may be necessary to shim under
one side of the hoist to make it level.
The hoist must be checked in two directions, one at 0 degree
and the other is above 45 degrees boom angle on any crane
that the hoist is not mounted directly to the boom, stationary
mounted.
Check the hoist at 0 degree to see if the hoist is aligned to
the boom nose sheave. The main hoist is aligned to the right
hand sheave and the auxiliary hoist is aligned to the center
sheave.
NOTE:
The hoist cable will have gaps in it during spooling
if the alignment is not correct.
NOTE:
The hoist is not level if the cable is piling up on one
side of the drum.
1.
The boom must be extended one half of full extension on
all hoist alignments. This length is used because when
the main hoist cable is positioned on the top right hand
boom nose sheave, the cable must leave the center of
the drum at a 90 degree angle. The boom has the ability
to extend, retract, and change the angle of departure
from the drum. Extend the boom half way to provide a
center point of adjustment to check the fleet angle of the
cable.
2.
All the cable must be removed from the hoist drum to
check the fleet angle. Using mason cord or cat gut
fishing line you will be able to pull the line tight to make
an accurate measurement of the fleet angle. Find the
centerline of the hoist drum by using a square and
drawing a line horizontal on the drum. Put a line vertical
to the horizontal line in the absolute center of the drum
WARNING
Failure to implement and adhere to a hoist inspection and
maintenance program may result in damage to the crane,
other property damage, and/or serious injury or death to
persons working on or near the crane.
Reference Only
