Attachment In Multi-Leg Suspension Gear; Symmetrical Loading; Asymmetrical Loading; Balancing Rocker - Pfeifer GK 8 Manual Del Usuario

3.2 Attachment in Multi-leg
suspension gear
For multi-leg chain suspension gear, angles of
inclination less than 15° should be avoided and angles
of inclination greater than 60° are not permissible. To
exclude overloads, the number of chain legs that may
be categorized as load-bearing should be checked by
a qualified person for each lifting procedure.
In general, in the four leg suspension, depending on the
nature of the load, three or two load-bearing chain legs
should be assumed. In the three leg suspension three or
two chain legs are assumed as load-bearing, depending
on the nature of the load. In addition, the attachment
method can have an influence on how many chain legs
may be loaded. When using mobile cranes, in general
only two chain legs are considered load-bearing. These
specifications apply only for symmetrical loads.
Amongst other things, EN 818-6 and DGUV rule
100-500 should be observed here along with applicable
country-specific regulations. In the case of asymmetri-
cal loads, as explained in the following, the carrying
capacity must be reduced.

3.3 Symmetrical loading

For this application, it is important to ensure
a symmetrical loading of the chain legs. This is the only
way to guarantee that the weight of the load to be lifted
is uniformly distributed to all of the chain legs. The load
can still be considered symmetrical when all the
following conditions are met:
• The load amounts to less than 80 % of the rated
carrying capacity
• The angles of inclination of all chain legs are not less
than 15°
• The angles of inclination of all chain legs are equal or
differ from one another by a maximum of 15°
• In the case of three and four leg chain slings the
angles corresponding to each other on the attachment
plane deviate by a maximum of 15°

3.4 Asymmetrical loading

In the case of an asymmetrical load of the chain legs
the carrying capacity must be reduced. In case of doubt
only one chain leg is assumed to bear the entire weight
of the load. Corresponding specifications can be found
e.g. in the carrying capacity tables on page 4. Please
also note DGUV rule 100-500.

3.5 Balancing rocker

Using a balancing rocker for a symmetrical load of the
chain legs in the four leg suspension means that all four
chain legs are considered load-bearing. The angle of
inclination of the rocker must not exceed 15°. This does
not apply for an asymmetrical load distribution!
Fig. 3.5.1: Balancing rocker

3.6 Chain shortening

The length of the chain can be varied by using chain
shorteners. This is necessary in order to largely
compensate asymmetries in the arrangement of
attachment points, so that the load is lifted horizontally
and stably. The desired length from the attachment point
to the shortening hook is to be set and subsequently the
nearest chain link is inserted into the slot of the hook. It
may be necessary to make adjustments.
CAUTION: Dangerous situation with threat
of damage to property if it is not avoided.
Using chain shorteners does not lead to a symmetrical
load distribution!
Shortening may only take place using shortening hooks
or claws. Pay attention to correct use during shortening
and load transport.
CAUTION: Incorrect use may cause the
load to fall.
Prior to each lifting check the position of the chain in the
shortening element.
Chain slings 11/2019 / Subject to change!
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