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FOREWORD
4. Precautions for sling work and making signs
1) Only one appointed worker must make
signs and co-workers must communicate
with each other frequently. The appointed
sign maker must make specified signs
clearly at a place where he is seen well from
the operator's seat and where he can see
the working condition easily. The sign maker
must always stand in front of the load and
guide the operator safely.
•
Do not stand under the load.
•
Do not step on the load.
2) Check the slings before starting sling work.
3) Keep putting on gloves during sling work.
(Put on leather gloves, if available.)
4) Measure the weight of the load by the eye
and check its center of gravity.
5) Use proper sling according to the weight of
the load and method of slinging. If too thick
wire ropes are used to sling a light load, the
load may slip and fall.
6) Do not sling a load with 1 wire rope alone. If
it is slung so, it may rotate and may slip out
of the rope. Install 2 or more wire ropes
symmetrically.
k
Slinging with 1 rope may cause turn-
ing of the load during hoisting, un-
twisting of the rope, or slipping of
the rope from its original winding po-
sition on the load, which can result
in a dangerous accident.
7) Limit the hanging angle to 60°, as a rule.
Do not sling a heavy load with ropes forming
a wide hanging angle from the hook.
When hoisting a load with 2 or more ropes,
the force subjected to each rope will
increase with the hanging angle. The table
below shows the variation of allowable load
in kN {kg} when hoisting is made with 2
ropes, each of which is allowed to sling up
to 9.8 kN {1,000 kg} vertically, at various
hanging angles. When the 2 ropes sling a
load vertically, up to 19.6 kN {2,000 kg} of
total weight can be suspended. This weight
is reduced to 9.8 kN {1,000 kg} when the 2
ropes make a hanging angle of 120°. If the 2
ropes sling a 19.6 kN {2,000 kg} load at a
lifting angle of 150°, each of them is sub-
jected to a force as large as 39.2 kN {4,000
kg}.
PC200/220(LC)-7
8) When installing wire ropes to an angular
load, apply pads to protect the wire ropes. If
the load is slippery, apply proper material to
prevent the wire rope from slipping.
9) Use the specified eyebolts and fix wire
ropes, chains, etc. to them with shackles,
etc.
10) Apply wire ropes to the middle portion of the
hook.
•
Slinging near the tip of the hook may
cause the rope to slip off the hook during
hoisting. The hook has the maximum
strength at the middle portion.
11) Do not use twisted or kinked wire ropes.
12) When lifting up a load, observe the follow-
ing.
•
Wind in the crane slowly until wire ropes
are stretched. When settling the wire
ropes with the hand, do not grasp them
but press them from above. If you grasp
them, your fingers may be caught.
•
After the wire ropes are stretched, stop
the crane and check the condition of the
slung load, wire ropes, and pads.
•
If the load is unstable or the wire rope or
chains are twisted, lower the load and lift
it up again.
•
Do not lift up the load slantingly.
SAFETY NOTICE
00-5
(14)
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