Manitowoc Published 10-01-2012, Control # 045-08 5-25
777 SERVICE MANUAL HOISTS
5
Load Block and Hook-And-Weight Ball
Maintenance and Inspection
The operating condition of the load block and the hook-and-
weight ball can change daily with use. They must be
inspected daily (at start of each shift) and observed during
operation for any defects which could affect their safe
operation. Correct all defects before using the load block or
the hook-and-weight ball.
Daily inspection and maintenance will include the following
points (see Figure 5-23 and 5-24):
1. Clean load block or the hook-and-weight ball.
2. Lubricate sheaves (if fittings provided), hook trunnion,
hook swivel, and any other part with a grease fitting at
the intervals specified in Lubrication in Section 9 of this
manual.
3. Tighten loose tie-bolts, cap screws, and set screws.
Check that all cotter keys are installed and opened.
4. Check sheaves for uneven wear in the grooves and on
flanges. Check for loose or wobbly sheaves. These
conditions indicate faulty bearings or bushings.
5. Check the fit of wire rope in the groove of each sheave.
An oversize wire rope can crack the lip of sheave flange
causing rapid wear of wire rope and sheave. The groove
must be larger than wire rope, and the groove must be
free of rough edges and burrs.
6. Check that hook, trunnion, and swivel rotate freely
without excessive play. Faulty operation indicates faulty
bushings or bearings or inadequate lubrication.
7. Check swivel of hook-and-weight ball for the following
conditions:
• Overloading: Spin swivel by hand; if the motion is
rough or has a ratchet-like effect, swivel bearings
are damaged.
• Side loading: Swivel will turn freely in one spot and
lock-up in another. This condition can also be
checked by looking at the gap (see Figure 5-23)
between barrel and shank (swivel must be removed
from weight ball to check); if the gap is wide on the
side and closed on the other, damage is present.
The gap between barrel and shank is normally 0.020 to
0.050 inches. If the gap increases, swivel-bearing failure
is indicated.
WARNING
Falling Load Hazard!
To prevent load from dropping due to structural failure of
load block or hook-and-weight ball:
• Only use a load block or a hook-and-weight ball
which has a capacity equal to or greater than load to
be handled.
• Do not remove or deface nameplate (Figure 5-22)
attached to load blocks and hook-and-weight balls.
• See “Duplex Hook” topic in Section 4 of Operator’s
Manual for recommended sling angles and capacity
restrictions when load block has duplex or
quadruplex hook.
FIGURE 5-22
CAP.
WT.
MANITOWOC
U.S. TON
LB’s.
NO.
SERIAL NO.
Maximum
Capacity
Weight
of Unit
Manitowoc Part Number
of Unit
Hook-and-Weight Ball
Check
Gap
Here
FIGURE 5-23
A923
Swivel
Item Description Item Description
1 Dead End Clip
6
Hook Latch
2 Socket and Wedge
7
Nameplate
3Tie Bolts
8
Shank
4 Weight Ball
9
Hook Swivel
5Hook
10
Barrel
1
2
3
4
5
6
7
8
9
10
3
9
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