2
3
Function
The load hook is raised or lowered by pulling on the hand chain. The load will remain where it is even when the hand chain is released because of
the effective reaction brake.
Suspension of chain block
Suspend the block from an eye, shackle, girder trolley etc. with sufficient load capacity. With the chain tightened, both hooks must be vertically
aligned.
NB!
No bending stresses may be applied to block, hooks or load chain.
Raising/lowering
Only use straps and slings of sufficient load capacity. Check that the load is not anchored to the floor/ground or is otherwise fixed before making
the lift. Ensure that the load chain hangs vertically and has no kinks. The hand chain must also be in good condition and easily accessible. The
load is raised or lowered by pulling the hand chain in either direction.
Warning:
Do not overload the brake by prolonged lowering. It may cause brake function to fail.
Warning:
•
Only hand power from a single person is permitted on the hand chain. If the chain feels too heavy, use a bigger chain block or reduce the load.
•
Make sure no-one stands beneath a hanging load.
•
Do not step onto a hanging load.
•
Do not raise or lower so far that the load hook hits the block housing.
•
The chain block must not be used for pulling loads.
•
The block must not be subjected to dynamic stresses, for example where a load connected to the block is launched from a height.
•
Do not leave a block with a suspended load unattended.
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 entails special risks. This is 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 chain hoist must bear.
In cases where heavy, bulky loads must be handled and it is not possible to estimate all factors correctly, the working load limit (WLL) of each
chain 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.
