2
3
Attachment of loads
Check the equipment before use. Improper attachment of loads can be highly dangerous (see Figs. 2 a – 2 e).
Fig 2 a
The sling is applying
load to the hook tip
Fig 2 b
Excessive top angle
on sling!
α max 60°
Fig 2 c
Hook latch
obstructed
Fig 2 d
Hook tip
subject to additional
bending stress
Fig 2 e
Load chain must not
be used as a sling
Multiple lifting
Multiple lifting presents special risks. This is when two or perhaps more hoists are used simultaneously for the same load. Danger to persons and
material damage can arise due to dynamic stresses and uneven load distribution causing individual hoists to become overloaded. A competent
person with experience in multiple lifting must therefore supervise this type of lifting tasks.
The total weight of the target object and its load distribution must be known or calculated.
For a variety of reasons, the centre of gravity can be difficult to determine, and thus so will the distribution of the load each hoist must bear. In
cases where heavy, bulky loads must be handled and it is not possible to estimate all factors correctly, the max working load limit (WLL) of each
hoist must be reduced by at least 25%.
Daily checks
After every working day on which the chain block has been used, the following should be checked:
•
Is the chain block deformed or otherwise damaged? Are any parts missing?
•
Is any deformation or other damage visible on the suspension device (eye, shackle, bolt, trolley etc.)?
•
Are the hooks intact or have any hooks opened? Are the hook latches correct and functional?
•
Wipe down the chain block and oil the load chain as required.
•
The load chain must be undamaged, i.e. no signs of wear and no deformed or otherwise damaged links.
•
The load chain must not be kinked or twisted. With two-fall or multi-fall chain blocks there is a risk of the chain twisting if the bottom hook
assembly ends up looped through the chain sling – usually during refitting or moving the chain block between work stations. See Fig 3.
•
The hand chain must also be in good condition.
•
The brake function must be intact.
In the event of faults or failures, the block must be repaired and carefully checked by a specialist before reuse.
Continuous maintenance - lubrication
Oil the hook latches and bearings. Grease the pawl and ratchet and also the gear. Lubrication must be sparingly and carefully applied so no grea-
se gets on the brake disk. Oil the load chain for longer life.
Periodic checks
Periodic checks are normally carried out yearly to detect and remedy any faults. If required (e.g. high frequency of use), more frequent checks
may be carried out. See “Checklist for periodic checks”. Measure hooks and chain to detect any changes in shape.
Checks on load hook
(see Fig. 4 and Table 1)
Opening dimension l on the hooks is important. A hook with too
large a maximum dimension has been exposed to overloading
or overheating. It therefore does not have the necessary load
capacity. The hooks may also have been exposed to long-term
wear (dimension K).
Hooks must be discarded and replaced if:
•
The maximum l value is exceeded (according to Table 1)
•
The minimum K value falls short (according to Table 1)
•
The hook shows signs of cracking
•
The hook is deformed or otherwise damaged
Defective hooks must be replaced before using the chain block
again.
Fig. 3 The chain must not be twisted Fig. 4 Load hook
