20
Ⅲ
. Uses and Operations
3) Precautions for Installation and Usage of PULLEY-MAN
❶
Requirements for an overhead structure to fix PULLEY-MAN or wire-hook:
●
Should be hard enough to endure load weight.
●
When fixing PULLEY-MAN to a shackle at tip of an extension arm, length of the extension arm should not
be too long. Consult table below for appropriate dimensions of extension arm with regard to moment,
bending stress, etc
❷
Selection of Material for Binding Load
①
Steel Wire Rope
●
Connection must be made at its tips and there must be no twisting or folding in between.
●
It must have safety factor of at least 5 times the load.
②
Chain
●
A chain with welded connection must be connected in short-connection mode.
●
It must have 4 times safety factor of the load.
③
Fibrous Rope or Sling
●
Except for one without open ends, connection must be made at its tips and there must be no twisting,
folding or knot in between.
●
It must have at least 7 times safety factor of the load.
❸
Methods of Binding Load with Wire Rope or Chain (See table & drawings below.)
●
Find center of weight before hooking.
●
Bind the load at least twice with a proper binding wire or chain.
●
When lifting load, make inner angle between top of load and binding material less than 60° Otherwise, rope or
chain may break off due to load weight.
●
When hooking load, place binding material on center of hook.
●
Hook must have a protective gateway latch to prevent binding material from slipping off.
