BAB 8: EXCAVATORDef:An excavator is an engineering vehicle consisting of a backhoe and cab mounted on a pivot (a rotating platform) with tracks or wheels mountings.

Excavators are large backhoes used for heavy construction.The types: track mounted, truck carrier mounted or self-propelled wheel mounted.Most excavators are on tracks.Wheeled excavators are used where mobility of operation is the primary concern.Wheeled excavators are popular heavy equipment used for mining large volumes of soil, coal or ore and civil engineering. These excavators are hydraulic powered.Consist of three structures: the revolving unit, the travel base, and the attachment.

Track-mounted excavator

Track-mounted excavator

Truck carrier-mounted excavator.

Self-propelled wheel-mounted excavator

Wheel-mounted excavator

EXCAVATORExcavators are used in many roles:

Digging of trenches, foundation Demolition Heavy lift, e.g. lifting and placing of pipes River dredging Mining

EXCAVATORTrenches

EXCAVATORFoundation

EXCAVATORDemolition

EXCAVATORHeavy lifting

EXCAVATORRiver Dredging

EXCAVATORMining

EXCAVATORAll excavators are designed to move large amounts of soil and earth in a minimal amount of time. Excavators come in a wide variety of sizes.The smaller ones are called a mini-excavator or compact excavator.Mini excavators are most often found at work at construction sites in densely populated urban areas. Often the bucket can be replaced with other tools like a breaker, a grapple or an auger. Grapples are similar to claws and are used to grasp objects (trees, stumps, etc). Augers are similar to a drill bit.

EXCAVATORMini / Compact Excavator

EXCAVATORBreaker

EXCAVATORGrapple

EXCAVATORAuger

ATTACHMENTS

All hydraulic excavator attachments are made of three strong structural members: the boom, the dipper stick, and the bucket.The structural members are hinged to each other, and the boom is hinged to the revolving unit.

Hydraulic excavator structural members.

Boom

The boom is normally concave towards the ground that allows space to pull the bucket closer to the excavator and permits deeper digging without interference from the travel unit.

Dipper Stick

The dipper stick is usually one-piece.

The bucket is connected at the end of the dipper stick .

Bucket

Buckets are supplied in a number of widths, ranging from 24 to 59 inches or more.

A bucket is usually slightly wider at the opening to reduce friction at the sides when diggingand to allow easier dumping.

Types of Excavators Compact excavator (Mini Excavator)Dragline excavatorBucket-wheel excavatorLong-reach excavator

Compact excavator

Dragline excavator

Dragline excavation systems are heavy equipment used in civil engineering and surface mining. In civil engineering the smaller types are used for road and port construction. A dragline bucket system consists of a large bucket which is suspended from a boom (a large truss-like structure) with wire ropes. The bucket is maneuvered by means of a number of ropes and chains.

Dragline excavator

Bucket-wheel excavator

Bucket-wheel excavators are heavy equipment used in surface mining and civil engineering. They are among the largest vehicles ever constructed.

Bucket wheel excavator

Long reach excavatorThe long reach excavator or high reach excavator is a development of the excavator with an especially long boom arm, that is primarily used for demolition. is designed to reach the upper stories of buildings that are being demolished and pull down the structure in a controlled fashion.

Long reach excavator

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