SAFETY DEVICES

ON CRANE
 Safety
Safety Devices
Devices on
on Crane
Crane

 1. Anti two block switch

 2. Host Limit Switch
 3. Boom Limit Switch
 4. Slew Limit switch
 5. Angle sensor
 6. Load Cells & Load movement indicator
 7. Aircraft light and flood lights
 8. Emergency Load Lowering & Slewing
Procedure
 1.
1. Anti
Anti two
two block
block Device
Device

Anti-two block Device helps the operator protect

equipment, loads, and personnel by preventing the
hook block from colliding with the boom.
1.
1. Anti
Anti two
two block
block Device
Device
 1.
1. Anti
Anti Two
Two Block
Block Device
Device

A2B: WHP-A/B: A2B electrical type, STNS/STNN hydraulic type : A2B

 2.
2. Hoist
Hoist Limit
Limit Switch
Switch

 Hoist limit switch is a safety device to allow the

hoist to travel within a prescribed travel range.
 Hoist Limit switch is operated through drum shaft.
Contacts within the limit switch are automatically
reset the motion is driven in the opposite direction.
 2.
2. Hoist
Hoist Limit
Limit Switch
Switch
 Main Host Limit Switch
 Fly Host Limit Switch
 Limit Switch for boom lowering and raising

Fly Host LMS

Main Host LMS Boom LMS

 3.
3. Boom
Boom Limit
Limit Switch
Switch
 A limit switch mounted on crane floor to prevent the
maximum boom angle is reached which can cause
overturned crane.
4.
4. SLEW
SLEW STOP
STOP LIMIT
LIMIT SWITCH
SWITCH (PROTECT
(PROTECT THE
THE
WHP
WHP BOOM
BOOM FLARE)
FLARE)
 The slew control is fitted with mechanical operated
valves, which stops the motion and apply the brake
when tripped.
 5.
5. Angle
Angle Sensor
Sensor

 Boom Angle Indicator & Sensor are used in

applications to warn an operator of the working angle
of a machine for safety purposes
 Boom Angle indicators is normal mounted on the
back side of a boom where they can easily be read by
the operator.
5.
5. Angle
Angle Sensor
Sensor
 6.
6. Load
Load Cell
Cell &
& safety
safety load
load indicator
indicator

 Load cell is a transducer device used to convert

force or weight into an electrical signal.

 Safety load indicator is key to helping the operator.

Not only does it prevent the operator from lifting a
load over capacity, but also gives the operator crucial
information. Such as the radius the crane is at, what
angle the boom is at and what the weight of load that
is currently being suspended
6.
6. Load
Load Cell
Cell &
& safety
safety load
load indicator
indicator
6.
6. Load
Load Cell
Cell &
& Safety
Safety load
load indicator
indicator
 7.
7. Aircraft
Aircraft light
light and
and flood
flood lights
lights

 Aircraft light used to alert aircraft and prevent air

traffic accidents when the crane is working.
 Flood lights be used to illuminate a large area
when the crane at working at night or in low light
conditions
7.
7. Aircraft
Aircraft light
light and
and flood
flood lights
lights
8.
8. Emergency
Emergency Load
Load Lowering
Lowering &
& Slewing
Slewing Procedure
Procedure
WHP
WHP BB
8.
8. Emergency
Emergency Load
Load Lowering
Lowering &
& Slewing
Slewing Procedure
Procedure
WHPB
WHPB
8.
8. Emergency
Emergency Load
Load Lowering
Lowering &
& Slewing
Slewing Procedure
Procedure
WHPB
WHPB
8.
8. Emergency
Emergency Load
Load Lowering
Lowering &
& Slewing
Slewing Procedure
Procedure
TBVN
TBVN
8.
8. Emergency
Emergency Load
Load Lowering
Lowering &
& Slewing
Slewing Procedure
Procedure
TBVN
TBVN