Chain Shortening; Attachment Methods - Pfeifer HIT GK 8 Traducción Del Manual Original

4.6 Chain shortening

The length of the chain can be varied by using chain
shorteners. This is necessary to largely compensate
asymmetries in the arrangement of attachment points,
so that the load is lifted horizontally and stably. Set the
desired length from the attachment point to the shor-
tening hook and insert the nearest chain link subse-
quently into the slot of the hook. It may be necessary
to make adjustments.
CAUTION: Dangerous situation with risk
of damage to property if it is not avoided.
Using chain shorteners does not lead to a symmetrical
load distribution!
Shortenings may only be adjusted with shortening
hooks or claws. Pay attention to correct use when
shortening and transportation of loads.
CAUTION: Incorrect use may cause the
load to fall.
Always check the position of the chain in the shortening
element before lifting.
Attach only when you have made sure that the chains
are not slipping, as shown in the example:
Fig. 4.6.1: Correct
Coupling turnbuckle
When using a clevis turnbuckle for adjusting the chain
leg length in a chain sling, the use of a securing chain
is mandatory, so that the clevis turnbuckle cannot
become unscrewed. So, ensure that the installation is
done correctly. This is not necessary if the coupling
turnbuckle has an automatic stop collar. The clevis
turnbuckle must be approved for use in chain slings.
Fig. 4.6.2: wrong
Impacts
Loading must be impact-free. When there is a risk of
severe impacts, for example if the load falls into the unloa-
ded chain sling, using the chain sling is not permitted.
When there is a risk of medium impacts, e. g. caused by
the slipping of the chain sling during its adjustment to the
shape of the load, the working load limit should be reduced
by at least 30 %. Any dynamic force should be avoided.
The chain legs must be aligned twist-free and straight (not
knotted). Suspension rings and hooks or other accessories
as connecting elements to the load or to the crane hook
must also move freely and be able self-align in the load
direction.

4.7 Attachment methods

Chain slings can be attached to the load in several ways:
Direct attachment method
In direct attachment, attachment parts are connected
directly to the attachment points on the load. The
compatibility of hooks and attachment points must be
taken into account so that the load is applied at the base
of the hook and excluded at the hook tip. The safety
latch or flap must be closed.
In the case of multi-leg chain slings the hook tip should
point outwards, unless the hooks are specially designed
for a different use. The orientation of the hook tip can be
changed by turning the suspension ring upside down.
Laced attachment method (Choker hitch)
In this case the chain legs of the chain sling are guided
through or under a load and the attachment part is
suspended or reeved on the chain (see Fig. 4.7.1).
This attachment method can be used when no suitable
attachment points are available and it offers the additio-
nal advantage that the chain sling bundles the load.
When using the choker hitch, the working load limit (WLL)
of the chain sling is limited to 80 % of the tagged WLL.
Fig. 4.7.1: Laced attachment method
Chain slings 12/2021 / Subject to change!
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