Appendix: Important notes for crane operators and crane operating companies
© 2009 Hirschmann Automation and Control GmbH · Branch Office Ettlingen · eMail: [email protected] · www.hirschmann.com
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24 183 19 1012e (Generic) / 2009-02-26 / Rev. 01 / rk.
NOTICE 3
Important information for the crane operator
In the Federal Republic of Germany, the guidelines of the Association of German Engineers
[Verein deutscher
Ingenieure]
VDI 3570 apply for the design of overload protections for cranes. They also make reference to the
sense and limits of overload protections.
“Overload protections are intended as far as possible to prevent accidents, risks to people and property, the
load and the crane during the operation of the crane due to overloading. The operator and crane driver must
take into account that an overload protection cannot detect all risks in time and a malfunction due to
undetectable factors is possible. You therefore must continue to exercise caution and remain responsible for
compliance with the operating specifications and loading of the crane. Overload protections are not to be used
operationally. They are only to be used in an emergency. The load-bearing capacity of the lifting gear is not to
be reduced by an overload protection.”
VDMA notice for overload protections (load moment limiters) on boom cranes
The boom crane supplied to you is equipped, in accordance with §24 of the UVV “Boom crane”, with an overload protection
(overload cut-out), by which the lifting gear and the boom retractor of the crane are switched off if the admissible load
moment is exceeded. To be able to remove a load after actuating the overload protection, movement in the opposite
direction must still be possible. It must therefore still be possible to lower the load, e.g. after disabling the lifting gear.
Fitting the overload protection (overload cut-out) is intended to prevent the crane from picking up loads which endanger its
stability. The overload protection (overload cut-out) is thus an emergency switch which, in the event of the crane being
overloaded, disables all movements which would increase the load moment and thus prevents possible damage or injury.
For the overload protection to perform its function as a safety device, the following must be observed:
1. Overload protections (overload cut-outs) are not to be used in normal operation to switch off the lifting gear of the boom
retraction device. The crane driver must in any event check for himself that the crane’s carrying capacity is not
exceeded by the load to be lifted. Excessive loads above the carrying capacity of the crane are not to be lifted despite
an overload protection being fitted. Nor should the overload protection ever be used as scales and the crane must not
be loaded above the highest maximum load in any case.
2. Fixed loads may only be pulled off in agreement with the manufacturer and only with cranes set up specially for this.
When used in this way, the overload protection (load moment limiter) may not be used as an operational device for
measuring force.
3. The overload protection fitted must be maintained on a regular basis and its functional reliability must be checked before
work commences. In accordance with §35 of the UVV “Boom crane”, the regular testing of the overload protection is part
of the crane maintenance.
4. The overload protection does not automatically adjust to the crane’s different modes of operation. The crane driver
therefore must adjust the overload protection to the altered carrying capacity or load moment range when the crane's
mode of operation changes. Here, the manufacturer’s instructions for the overload protection fitted are to be observed.
The reliable functioning of the equipment and accident-free operation of the crane depend heavily on the careful
observation of these provisions. An incorrectly set overload protection, e.g. a high load moment when the supports are
retracted, is substantially more dangerous than a crane without an overload protection as it can give the crane driver a
false sense of security; this can lead to serious accidents.
