Front Shovel Description
and Uses
Excavators where
the digging action is an upward motion are called front shovels
or just shovels. The front shovel perform excavation by crowding
the material away from the machine.They are mainly used for digging
above the track level and loading the material into hauling units.
Thus they are suitable for use in quarries for loading of blasted
or short rocks. A typical modern shovel
is depicted in the diagram below.

A
Front Shovel Diagram
A front shovel
has the capacity to develop high breaking force. This is required
as the material being excavated should be such that it will stand
on its own almost at a vertical face. And normally such material
are rocky in nature. Usually the front shovel are mounted on track
base and have a slow traveling speed. The other basic parts of a
shovel consist of the mount, cab, boom, stick and the bucket as
shown in the figure below. The size of a shovel is indicated by
the weight and bucket size.
A front shovel
has to be close to the material to be excavated before it begin
excavating. When this is achieved, the bucket is lowered to just
above the track level with the bucket teethes pointing into the
material face. A crowding force is applied by hydraulic pressure
to the stick cylinder and at the same time the bucket cylinder rotates
the bucket through the face.
The bucket
will be fully filled if the height of the of the excavated material
is right. If the material height is too low a second pass will be
required. Then once the bucket is full it just tipped over to load
the material into hauling units. Finally the material left on the
pit floor will be excavated after the upper material is excavated.