Basics of crane

Training programme for Crane Users 1
BASICS OF CRANES

Crane
Crane is a machine meant for lifting or lowering a load and
moving it horizontally or slewing it to left or right and in
which hoisting is an integral part of machine. It may be
driven manually or by power and may be a fixed or mobile.

Basic Principle of a Crane
A Crane,basically, is designed on the Principle of load
moment.
Xx ~ Yy
force force
x y
X Y
Fulcrum‘O’

TYPES OF CRANES
CRANES
Mobile Stationary
Crawler Mounted Tyre Mounted Overhead Pedestal Pole mounted
Mechanical
(TFC 280)
Hydraulic
(AM.11320)
Lattice
Boom
Telescopic Boom
Rough terrain (TIL RT 740B)
All Terrain
Truck Mounted (TIL 830 , AC 1600)
(Jib Crane)(EOT ,Gantry)

Boom Point Head
No. of falls
Hook Block
Boom Insert
Boom Bottom
Operator Cabin
Under Carriage
Crawler
Boom Top
Pendant Ropes
Outer Bail
Boom Hoist Rope
Boom Stoppers
Inner Bail Gantry
Counterweights

Telescopic
Boom
Operator
‘s Cabin
Winch (Main
Hoist)
Hook Block
Engine
Out Rigger
Derrick
Cylinder
Counter
Weight
Slew Ring
Wheels
Main Hoist Wire Rope
Boom Point
Sheaves
Hydraulic Crane -Components

Some
Definitions
Radius :-
Radius is the Horizontal distance at ground level, from
the crane centerline of rotation to a vertical line through the centre of
gravity of the suspended load on hook
Boom Length :-
Boom Length of main boom measured from Boom Pivot
to the Top Boom Point
Boom Angle :-
Boom Angle is the angle of Boom to the horizontal

Boom Point Height :-
It is the vertical distance between Boom Point
and Ground, measured perpendicular to the ground. It is also
referred as Boom Point Elevation.
Load Chart :-
It is a chart representing rated capacities of crane at
various radius w.r.t. various boom lengths,boom angle and
configuration.
Rated Capacity :-
Rated capacity of a given radius is the maximum
load permitted to be lifted by the crane at the particular radius.
These are calculated on basis of various factors such as
crane stability structural limitations etc. This also is called as
Safe Working Load or SWL.

Maximum capacity of Crane :-
This is the maximum capacity of a Crane and is
obtained at minimum radius with basic minimum boom length
of a crane. A crane is basically defined by the maximum
capacity only.
For example :- A 20 MT capacity crane can lift 20 MT load
only at its minimum radius and that too, with it’s minimum or
basic boom length only. Similarly a 500 MT crane can lift
500MT load at its minimum radius with minimum or basic
boom length only.
Propel :-
The term ‘Propel’ refers to marching /traveling of
crawler Cranes

O/R Width :
It is the distance between two opposite
outriggers measured from centre to centre of O/R loads with
outriggers in completely extended position.
O/R width
Crane

Crane- Basic Operations
Hoisting/Lowering :-
Hoisting or lowering of hook block
Swing (or slewing) :-
Slew of crane superstructure to either side along
with his own axis.
Boom Hoisting/Lowering :-
It is lowering or hoisting of boom with respect to its
pivot essentially to increase or decrease radius.
Marching (or Propelling) - in case of crawler cranes only
Travel of a Crawler Crane forward or reverse.
Telescopic boom extension/Retraction :-
Extending or Retracting of Telescopic Boom to
increase or decrease Boom Length

C
C
Engine Transmiss
ion
Pump1
Swivel UnitSwing Unit
Telescopic Boom
BoomHoist
Winch
Pump 2 & 3
Front Wheel
RearWheel
Control
Valve
Torque
Conv.
Schematic Of Power Train In
Hyd. Crane (Tyre Mounted)

Some Common Configuration Of
Cranes
Crawler Crane
 Main Boom
Main Boom plus fixed Fly jib(at various offset angles)
Main Boom plus Luffing fly jib (SW)
Main Boom with Super lift(SSL) or sky horse attachment(SH or
SSH)
Main Boom plus Luffing Jib/fly Jib + Super lift (SWSL/SFVL)

Some Configurations of Crawler Crane
Above example is of Demag CC2500 Crane

Some Configurations of Hydraulic –Tyre
Mounted Crane
Above example is for a specific model of Demag Crane

General Safety Features Of Crane
1. A2B (Anti Two Block) OR Over Hoist Limit Switch :-
Gives alarm (and trips off further hoisting), in
case of Hook Over Hoisting.
2. Boom Hoist Limit Switch (Crawler Cranes) :-
Generally a ‘Shut Off’ valve which gives alarm
in operator’s cabin (and cuts off further hoisting), when the
boom has reached to a pre-set (maximum) angle during
hoisting.
3. Overload Limit Switch (Hydra) :-
Gives a warning (alarm), in case the Hydra
approaches Overload condition.

4. Safe Load Indicator (SLI) :-
SLI, when fitted on crane, measures and displays
following data –
Radius of Hook
Boom Length
Boom Angle
Actual Load Lifted by Crane
Rated Capacity (SWL)
SLI is also equipped to provide :-
A2B condition, indication & Tripping in case of Over
Hoisting
Analog indication of Load Moment, in terms of Green
(Safe Zone), Yellow (Alert Zone) and Red (Danger &
Cut Off zone)
Indication, Alarm and Motion Cut Off, when an overload
condition has reached.

SLI on Hyd. Crane – General components
(Kruger Mark 4 on Voltas 40 crane-as an example)

Controlled Load Lowering In
Crawler Crane
Controlled Load Lowering (CLL) is a mechanism provided on Crawler
Cranes to achieve gradual lowering of Load (Hook) in a controlled
manner.
This is achieved by providing special mechanisms,like planetary system
or separate reduction achieved via chain and gears, in power train of
Hoist Lowering .
CLL is exactly opposite to the FREE FALL mechanism, possible on
Cranes, wherein the Hook is allowed to come down freely with the aid of
gravitational force. As the name ‘free fall’ clearly suggests, it does not
have control in lowering of Hook, except by applying brakes. And hence
‘free fall’, strictly, is not to be used on any crane.
It is pertinent to mention here that lowering speed,also depends upon
engine RPM and is in direct proportion of it.

Basics of crane

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