Hydraulic Excavators
By
Er. Ashok Shrestha (DoR)
IOE-BEM
Construction Equipment (Elective) August 2010
Hydraulic ExcavatorHydraulic Excavator is the most commonly used construction machine. it has bucket with
specified volumetric capacity.
Hydraulic power is the key utility to operate the
hydraulic excavators.
Excavator can work above and under the ground level where it rest.
It can work at all gradient and difficult terrain and even under water excavation work where other
machine can not be used.
With various front attachments, it can be used for
diversified purposes.
Most excavators are mounted on track base, but
smaller model may be mounted on wheels base.
16 August 2010 Slide No. 2IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavator: Main Parts• A hydraulic Excavator consists THREE major parts
1. Work EquipmentThis part consist
working tools for
digging and loading
2. Upper StructureThis part consist engine, cabin
and holds components such as
operator’s seat controlling
joysticks and monitoring gauges
3. UndercarriageThis part consist Crawler/
track chain or Wheel for
moving machine on the
ground.
16 August 2010 Slide No. 3IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Arm Cylinder
Work Equipment: Work equipment is designed
to run by hydraulic cylinders
Oil Pressure Inside the
cylinder is the key factor to
overcome require FORCE to
do work.
Oil flow rate inside
cylinder is key factor to
move and speed up and
down of work equipment
Rod Cylinder
Piston
Force
=
Pressure x Area
16 August 2010 Slide No. 4IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Upper Structure: Cabin Interior
Depending on
moving direction of control Lever/
Pedals Machine
can move
straight or turn
left or right.
Depending on moving direction of control Joystick Boom, Arm or Bucket can
be moved for doing work or machine can swing to require degree of rotation
Cabin Interior
Travel LeversMachine monitoring units
(Temp., Press. Gauges)
Work equipment
control Joystick
Engine starting
switch
Fuel gauge
Lights / Other
switches
Travel
Pedals
Work equipment
control Joystick
Operator’s
seat
16 August 2010 Slide No. 5IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Arm/Swing Controls (Left Joystick)move forward and backward to move Arm out and in
move left and right to control direction of swing
Boom/Bucket Controls (Right Joystick)move forward and backward to lower and raise boom
move left and right to control bucket curl and dump
Excavators: Swing mechanism
Pinion Outer race
Inner race
Ball bearings
SWING CIRCLE
The outer race fixed at upper structure turns with the “Pinion” that spins along with the inner race fixed at the lower structure.
The part between the outer race and the inner race turns smoothly on the ball bearings.
This part enables an hydraulic excavator to turn around
Stick/Swing Controls (Left Joystick)move forward and backward to move stick out and inmove left and right to control direction of swing
16 August 2010 Slide No. 6IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Lower Structure:UndercarriageMost are Crawler/ Track type.
Compared to the Wheel type, the
Crawler type has more part touching
the ground. Which enables them to
work on muddy surface where Wheel
type can not be used.
WHEEL
(TYRE)
Seen from the sides
Seen from the underneath
CRAWLER / TRACK
The part touching the
ground surface
Wheel type excavator
make use of supports/
Stabilizers during work.
Can also be fitted with dozing blade . (Optional)
16 August 2010 Slide No. 7IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavators: How it Works ?
Arm Cylinder Control Valves
Hydraulic Pump
Engine
Hydraulic Oil Tank
Swing Motor
Travel Motors
Boom Cylinder
Bucket Cylinder
Hydraulic Power is the key utility to operate all Hydraulic Excavators
16 August 2010 Slide No. 8IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Excavators : Types• Based on feet mounted on undercarriage they
are classified as:
1. Crawler or Track type
2. Wheel type
Both front SHOVEL type or HOE type Excavator can be mounted on either on a Crawler or a Wheel tractor base.
• Based on types of Bucket mounted or digging motion of bucket they are classified as:
1. Shovel type
2. Hoe type
16 August 2010 Slide No. 9IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavator: Front Shovel
• An upward motion unit is know as “front shovel”
• Hydraulic front Shovel excavators are used mainly for hard digging
above track level and for loading
hauling units.
• A shovel develops breakout force
by crowding material away from the machine.
• The boom of a shovel swings upward to load; so the machine
requires a material face above
the ground level
Basic Features:
16 August 2010 Slide No. 10IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavator: Hoe
• A downward arc unit is classified
as Hoe
• Hydraulic Hoe excavators are used primarily to excavate below natural
surface of the ground on which machine rest
• It develops excavation breakout force by pulling the bucket towards
the machine and curling the bucket
inward.
• The downward swing of a hoe
dictates usage for excavating below the ground level at which
machine rest
Basic Features:
16 August 2010 Slide No. 11IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavator• The hydraulic excavators are fully hydraulically
control machine which provides:
– Faster cycle time
– Less noisy
– Smoothness and ease of operation
– High overall efficiency
– Greater accuracy and precision
• It is a versatile machine that can be used for almost all kind of applications.
• A quick coupler enables to quick change with different type attachments and perform a variety of tasks in rapid succession
16 August 2010 Slide No. 12IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Excavator Specifications• Machine (Make/ Model/ Sr. No., overall dimension)
• Operating Weight (kN) (with operator,
cabin and all standard items & accessories)
• Engine (Make/ Model/ Sr. No./Type, Cly. No./stroke,
• CI/SI, Torque/ RPM/ Cooling type
• Flywheel Power (kW)
• Undercarriage (Track shoe size type,
• roller no., track length, ground pressure etc.)
• Hydraulic System– Swing Mechanism (Speed/ Torque)
– Drive System (Travel speed / Drawbar-pull)
– Work Implements (Pressure, Cylinder type size)
• Bucket (model, Cubic capacity)
• Performance Data (Working range, Arm force/ Bucket force)
16 August 2010 Slide No. 13IOE-BEM-CE(Elective): Dozers: By Ashok Shrestha
16 August 2010 Slide No. 14IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
16 August 2010 Slide No. 15IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Hydraulic Excavator: Application• Hydraulic hoe has evolved from a single purpose
excavating machine into a versatile multipurpose tool.
• It is a versatile machine that can be used for almost all kind of applications.
• Typical general applications are:– Digging under or above the ground level
– Canal/ Trench excavating and pipe laying
– Loading hauling units
– Lifting construction materials
• A quick coupler enables the hoe to change attachments and perform a variety of tasks in rapid succession. Some common attachments are:– Hydraulic breaker - Crane
– Clamshell - Rock driller
– Impact hammer - Demolition jaw
– Cutters - Land clearing grapple
16 August 2010 Slide No. 16IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Typical Applications
16 August 2010 Slide No. 17IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Attachments
Handling Scrap materialsBuilding demolishing
Various types of attachments
16 August 2010 Slide No. 18IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
Commonly used terminologies related to shovel/ bucket size rating
• Struck Capacity : – The volume actually enclosed
by the bucket with no allowance for bucket teeth
• Heaped Capacity:– Both PCSA and SAE uses a
1:1 angle of repose for evaluating heaped Capacity. CECE specifies 2:1 angle of repose.
18 August 2010 Slide No. 19IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha
PCSA – Power Crane and Shovel Association
SAE – Society of Automotive Engineers
CECE – Committee on European Construction Equipment
Fill FactorsFill factors:
The actual amount of material in a bucket needed for shovel production calculation. Fill factor are express in percentage which when multiplied by heaped capacity, adjust the volume by accounting for how specific material will load into the bucket.
16 August 2010 Slide No. 20IOE-BEM-CE(Elective): Excavators: By Ashok Shrestha