Important Notes
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19_1272E.DOC / 2001-04-02 / Rev. C / ko.
PAMPHLET 3 Important notes for crane users
In the Federal Republic of Germany, the directives of the Union of German Engineers VDI (Verein Deutscher
Ingenieure) 3570 are effective for the construction of safe load indicators. There, too, it is directed to the significant and the limits of the safe load indicator.
"Safe load indicators shall, during crane operation, hinder accidents, endangering of persons, things, the load,
the crane due to overload within the limits possible. User and crane operator must take into account that a safe
load indicator cannot realize all dangers in time and that a malfunction by non-perceptible influences indeed is
possible. Therefore they are not dispensed from circumspection and the responsibility to the observance of the
operating instructions and the load of the crane. Safe load indicators are not intended for regular operation.
They shall only respond in emergency cases. The capacity of the hoisting appliance shall not be reduced by
safe load indicator".
Instructional Pamphlet VDMA
for safe load indicators (load moment limiting devices) on boom cranes
The boom crane delivered to you has a safe load indicator (overload cut-off device) according to §24 of the accident prevention regulation UVV "boom cranes" which will cut off the hoist and boom hoist unit of the crane when exceeding the admissible safe load. The opposite movement must remain possible in order to be able to relieve the crane of the load after the safe
load indicator has reacted, e.g. it must be possible to lower the load when the hoist was cut off.
Installation of a safe load indicator (overload cut-off device) has the purpose to prevent the crane from lifting a load which
would endanger its stability. Hence the safe load indicator (overload cut-off device) is an emergency switch which, in the
event of overload, cuts off all movements increasing the load moment thus avoiding a possible damage or accident. The
following must be observed for the safe load indicator to comply with its function as a safety device.
1. Safe load indicators (overload cut-off devices) must not be used operationally to cut off the hoist or boom hoist unit. The
crane operator must in any case previously make sure that the load to be lifted will not exceed the lifting capacity of the
crane. Superheavy loads exceeding the lifting capacity of the crane must not be lifted even with a safe load indicator installed. The unit must not be loaded beyond the respectively admissible load.
2. Freeing loads which are stuck may only be effected in agreement with the crane manufacturer and with cranes especially
equipped for this purpose. During these jobs it is not allowed to use the safe load indicator (overload cut-off device) as an
operational unit for force measurements.
3. The built-in safe load indicator must be regularly serviced and checked as to its functional safety before starting operation. According to the accident prevention regulation UVV "boom cranes" §35 maintenance of the crane also includes
regular checks of the safe load indicator.
4. Generally, the safe load indicator does not adjust automatically to the various operating conditions of the crane. When
changing the operating condition of the crane, the operator is therefore responsible of changing the safe load indicator
over to the new load or load moment range as well. For this purpose, observe the manufacturers operating instructions
for the safe load indicator installed. Safe operation of the device and accident-free operation of the crane depend to a
high extent on careful observance of this instruction. Maladjusted safe load indicators, e.g. set to a high load moment
with retracted outriggers, are much more dangerous than cranes without a safe load indicator since the crane operator is
given a wrong feeling of safety which might be the cause of serious accidents.
5. When changing the crane over to various operating conditions, the safe load indicator installed must be changed over to
the new load or safe load ranges resp. by the crane operator, e.g.:
a) when extending or retracting the outriggers (changing over to high or little load moment);
b) when changing the boom length by: