Jib crane have the following motions:
- Hoisting motion
- Derricking or luffing motion
- Slewing motion
- Long travel motion
Hoisting motion:
It
is used to lift or lower the load. This is usually achieved by steel
wire ropes being affixed to a crane hook or a grab hanging from the
outer end of the jib. The rope is applied through some receiving
arrangement and controlled and operated by a winch system.
Derricking or Luffing motion:
It
is imparted to the inclined member or the jib to move in a vertical
plane so that the angle of the jib may be changed in order to bring the
load line nearer to or further off from the centre of the crane.
Slewing motion:
It is imparted to the whole super structure of the
crane including the jib, so that it can turn about a central pivot shaft
w.r.t. the non-revolving parts. This motion enables the crane to shift
the load line to revolve round the crane.
Long Travel Motion:
It may be required when the whole crane structure has to be shifted to a distant place along a rail track or along a road.
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