M A E D A Crawler Crane 5.4 CRANE OPERATION
5/2020 CC1908S-1 5-25
PRECAUTIONS WHEN OPERATING WINCH
• Select a number of falls that suits the hook and
a boom length that suits the mass of hoisted
load.
Refer to "6.18.1 WIRE ROPE" on P. 6-75.
• Do not allow persons to stand in the area
below the hoisted load.
• When hoisting a load, briefly stop when the
hoisted load leaves the ground to check
factors such as load stability and load force
before continuing to hoist up the load.
• Do not pull a load laterally, draw it in, or hoist it
diagonally. Otherwise, there is a risk of the
crane toppling or being damaged.
• Overwinding the hook block may result in
collision with the boom, breaking the wire
ropes or causing the hook block and load to
fall, resulting in a serious accident. Take care
not to overwind the hook block.
• Be careful to prevent the wire rope and/or
hoisted load from coming into contact with
obstructions such as trees or girders when
hoisting a load.
If the wire rope becomes entangled by an
obstruction, do not forcibly wind up the hoisted
load, but untangle the caught part before
winding up.
• Do not use the winch drum wire if it is wound
irregularly. Irregular winding can not only
damage the wire rope and reduce its service
life, but can also cause the wire rope to break,
resulting in a serious accident.
Adhere to the following precautions to avoid
the wire rope from winding up irregularly:
Do not let the hook block come into contact
with the ground by operating the winch lever.
When lowering the hook block a long
distance such as for underground work, be
sure to leave at least three turns of wire rope
on the winch drum.
• When decelerating from high-speed hoisting,
ease off the accelerator pedal to reduce the
engine speed, then slowly return the right-hand
control lever. Sharply returning the right-hand
control lever while maintaining a high engine
speed causes the hook to jump up due to the
rapid deceleration shock, resulting in irregular
winding.
• Use the winding and unwinding operations in
high-speed mode only when winding or
unwinding the hook alone. Raising and
lowering a hoisted load at high speed may
cause serious accidents due to the machine
toppling or damage to the boom or frame.
• If the wire rope becomes twisted and causes
the hook block to rotate, fully eliminate the
twisting before work.
Refer to "6.18.1.3 CORRECTING WINCH
WIRE ROPE TWISTING" on P. 6-78.
PRECAUTIONS WHEN OPERATING BOOM
• Operate the boom control lever as slowly as
possible.
Especially avoid sudden lever operations when
a load is hoisted, which may cause the load to
sway and hit the machine, damaging the crane
or causing the machine to topple.
• Lowering the boom increases the working
radius and reduces the rated total load that
can be hoisted. When derricking the boom,
pay extra attention so that the weight of the
load at the lowermost boom position does not
cause overloading.
• Never attempt to pull a load laterally or draw it
in by derricking or telescoping the boom.
• Take care when telescoping the boom to
check the winding of the hook block.
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