LOADERSEARTH MOVING EQUIPMENTS

LOADERS

• A loader is a type of tractor, usually wheeled, sometimes on tracks, that

has a front-mounted square wide bucket connected to the end of two

booms (arms)

• to scoop up loose material from the ground, such as dirt, sand or gravel,

and move it from one place to another without pushing the material

across the ground.

• to move a stockpiled material from ground level and deposit it into an

awaiting dump truck or into an open trench excavation.

FRONT LOADER

• the front loader is a type of

tractor that is normally wheeled

and uses a wide square tilting

bucket on the end of movable

arms to lift and move material

around.

• The loader assembly may be a removable attachment or permanently

mounted on the vehicle.

• Often times, the bucket can be replaced with other devices or tools, such

as forks or a hydraulically operated bucket.

FRONT LOADER

• Larger style front loaders, such as the

Caterpillar 950G or the Volvo L120E, normally

have only a front bucket and are known as

front loaders

• where the small front loaders are often times

equipped with a small backhoe as well and

called backhoe loaders or loader backhoes.

• Loaders are primarily used for loading

materials into trucks, laying pipe, clearing

rubble, and also digging.

FRONT LOADER

• Loaders aren’t the most efficient

machines for digging, as they

can’t dig very deep below the

level of their wheels, like the

backhoe can.

• Unlike the bulldozer, most loaders

are wheeled and not tracked.

• The wheels will provide better mobility and speed and won’t damage

paved roads near as much as tracks, although this will come at the cost of

reduced traction.

FACTORS AFFECTING PRODUCTIVITY

• The natural condition of the material to be loaded

• The bucket type and capacity as well as loading limits, which depend on

the material

• Maneuvering area for the loader operation

• Cycle time for the front-end loader

• The efficient operating hour for the operator

PRODUCTIVITY RATE

• Production rate is expressed in cubic yards per hour (cy / hr).

Production rate = capacity of bucket X number of passes per hour

Number of passes per hour = cycle time of loader / avg. no. of min. in each

hour

• Size of bucket is generally expressed as the SAE-rated nominal headed

capacity

PRODUCTIVITY RATE

• The cycle time is the time required ,

– To load the bucket with the material,

– To Back up to a convenient spot for turning

– To turn and move forward and dump into the truck

– To reverse directions

– To turn and move forward to dig the next load

The distance moved backward from loading the bucket to the turning point and

back may be 15 – 20 feet.

• The cycle time should be broken down to separate the variable times from

the fixed time.

PRODUCTIVITY RATE

• FIXED TIME (FT) – the time is constant irrespective of operation

(to load bucket, to turn, to dump, to shift gears)

• FT is in the range of – 0.25 – 0.25 min (15 – 21 sec)

• VARIABLE TRAVEL TIME (VT) – the time depends on travel speeds and the

distances traveled with loads.

• VT in a cycle includes the time spent travelling in both forward and reverse

gears

• The total cycle time CT = FT + VT

Gives the maximum productivity for the loader operating without any delays.

TONNAGE ESTIMATE

SAFETYOperate wheel loaders carefully because they are easy to overturn.

• Operators should adhere to the following safety practices:

Block the bucket when working on the machine.

Use caution when removing and replacing the lock rings.

Do not work between the wheels and the frame while the engine is running.

Use caution when operating close to the edge of a trench or when working under

overhangs created by digging into banks or stockpiles.

Travel with the bucket at or below axle height.

Do not carry or lift personnel in the bucket.

Ground the bucket and set the parking brake before leaving the machine.