H2 MANOEUVRES OF THE CRANE LOADS
(!) Before manoeuvering the load, verify that the working area is
suitable for your crane.
The lifting curves of the capacity plate indicate the maximum load that the crane
can lift at a certain radius and at a certain height.
To utilize the maximum capacity of the crane, it is necessary to position the
inner boom as indicated on the capacity plate; the coloured symbols on the
inner boom and column must coincide.
During load handling, do not exceed the reach limits given, or the load indicated
on the above mentioned charts. If the limits are exceeded, the load limiting devi-
ce, permitting the slow descent of one of the two, or both, lifting rams (or if the
jib is fitted: the jib outer ram) will be immediately activated.
H2.1 Load limiting device
The device called “load limiting device” utilizes a small main pressure valve
insered on the safety check valves of the crane inner and outer rams and of
the jib outer ram. When the intervention values are reached, these valves are
activated, permitting the slow descent of one of the two, or both, lifting rams
(or of the jib outer ram, when fitted) and preventing use of the crane in an over-
loaded condition.
To stop the load descent, it is compulsory to reduce the load radius towards
the column, operating the control lever to re-enter the boom extension rams of
the crane (or of the hydraulic extension if fitted) and carrying out a manoeuvre
which will reduce the moment on the column axis.
(!) This operation must be carried out within and not over five (5) seconds
from the beginning of the load descent.
(!) ATTENTION (!)
The presence of the load limiting device does not release the user from the
obligation to respect what is indicated on capacity plates and lifting curves.
Lifting moment limiting device
A characteristic which permits the classification of cranes is their lifting capa-
city or maximum lifting moment. The moment is defined by the value obtained
from the weight of the load to be lifted (kg) by its distance (meters) from the
centerline of the crane rotation.
The device called “lifting moment limiting device” preserves the crane structure from
overloads, as it prevents any movement which increases the value of the moment
up to the maximum established value.
H2
CONTROLS TO
OPERATE THE CRANE
F 170A
29
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