Power Shovels are used primarily to excavate earth and load
it into trucks.
They are capable of excavating all classes of earth, except
solid rock, without prior loosening, like in quarries, mines in
any road projects etc.
Power shovels are considered as basic tool for excavating
the materials and loading.
They may be mounted on crawler tracks, in which case they
are referred to as crawler mounted shovels. Such shovels
have very low travel speeds.
However, they may be mounted an rubber-tired wheels.
Single-engine self-propelled units are powered and operated
from excavator cab. The non-self-propelled units mounted
on the rear of tracks, which are referred to as truck-
mounted, have separate engines for operating them.
A dragline excavator is especially useful when
there is need for extended reach in excavating or
when material must be excavated from
Draglines are used to excavate material and
load it into hauling units or to deposit it in
levees and spoil piles near the pits from which it
A dragline bucket consists of three parts: the
basket, the arch, and the cutting edge.
Buckets are generally available in three
types: (1) light duty, (2) medium duty, and
(3) heavy duty.
Clamshells are used primarily to
remove materials from vertical
excavations such as cofferdams, pier
foundations, and sheet-lined trenches.
There are hydraulic clamshell buckets
that are mounted on the stick of
The two jaws of a clamshell bucket
clamp together when the bucket is lifted
by the closing line.
A backhoe, also called a rear actor or back actor,
is a piece of excavating equipment
or digger consisting of a digging bucket on the end
of a two-part articulated arm.
The section of the arm closest to the vehicle is known
as the boom, and the section which carries the bucket is
known as the dipper or dipper-stick .
The boom is generally attached to the vehicle
through a pivot known as the king-post, which allows
the arm to slew left and right, usually through a total of
around 200 degrees.
A trencher is a piece of construction
equipment used to dig trenches, especially for
laying pipes or cables, for installing drainage,
or in preparation for trench warfare.
Trenchers may range in size from walk-
behind models, to attachments for a skid
loader or tractor, to very heavy tracked heavy