STT113 TOWER CRANE OPERATION AND SERVICE MANUAL
8B
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13
6
5
1
2
4
3
VI. Load limiter
1. Purpose
The structure and hoisting winch of the crane are calculated and designed in
accordance with maximum load. It is not permitted that working load exceeds the
maximum load. The load limiter
MSWL
is a safety device to prevent the crane from
overload.
2. Working principle
When passing the pulley of the load limiter, the hoist wire rope produces tensile force
due to action of load. The tensile force is transmitted to the load limiter, which
connects with the pulley. As the load change, the load limiter begins distorting so as
the steel plate on which inching switches (2,5) and adjustable screw (1,6) is fitted also
distort accordingly (principle is the same as the moment limiter). According to the
requirement of the load, by proper adjustment, the inching switch (2,5) is depressed as
to control the circuit properly.
3. Adjustment
Fig. 8-6-1
1, 6 – adjusting bolt 4 – proving ring 2, 5 – sensitive switch 3 – metal strip
Note:
1) The tower crane should set 2 sensitive switches and adjusting bolts.
2) Except normal inspection and maintenance for the load limiter, after each erection
and changing falls, it must be readjusted according to characteristic parameters.
