HYDRAULIC EXCAVATOR

1. CHAPTER- FOUR
HYDRAULIC EXCAVATOR
By: Debas D.
1
Ambo University
Department of Mechanical engineering

2. Overview
• Introduction
• Hydraulic Excavator function
• Available sizes and categories
• Major components of hydraulic Excavator
• Specification of hydraulic Excavator
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3. Introduction
• Hydraulic Excavators are heavy construction
equipment consisting of a boom, dipper (or
stick), bucket and cab on a rotating platform
known as the "house".
• All movement and functions of a hydraulic
excavator are accomplished through the use of
hydraulic fluid, with hydraulic cylinders and
hydraulic motors.
• The excavator is used for digging and loading of
earth that is below the machine.
• The upper swing unit can rotate 360°.
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4. Excavator functions
 Excavators are designed for multiple applications including
clearing, backfilling, excavating and loading.
They can be equipped with numerous styles of buckets and
accessories.
Excavator has numerous functions such as;
• Digging of earth
• Loading
• Trenching
• Cutting
• Land clearing
• Leveling
• Drilling
• Compacting
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5. Digging of earth
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6. Loading
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7. Trenching
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8. Cutting
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9. Land clearing
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10. Leveling
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11. Drilling
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12. Compacting
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13. Available sizes
• Mini Excavators (300.9D, 301.4C, 301.5, 301.6, 301.6C,
301.7D, 301.8, 301.8C, 302.2D, 302.4D, 302.5, 302.5C,
302.7D, 302C SR, CR, 303E CR, 304, 304.5)
• Small (E110B, E120, E120B, E140, E180, E200B,
E240, E240B, E240C, E300, E300B, E450, E650,
EL180, EL200B, EL240, EL240B, EL240C, EL300,
EL300B, M312, M313C, M313C)
• Medium (215, 215B, 215C, 215D, 219, 219D, 224,
224B,324D, 324DL, 225, 225B, 225D, 229, 229D)
• Large (345D, 349D, 349E, 350, 365B, 365B II, 365C,
374D, 375, 385B, 385C, 390D) etc.
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14. Excavator categories
1. Crawler excavator:
• Crawler excavator runs on two endless tracks (chain system).
• These types of excavators are used in hilly areas where risks of
sliding of machinery are on the verge.
• Crawler type excavator has low ground pressure because of
spreading of load on large area.
• Therefore, it is also used where soil support is weak.
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15. Excavator categories
2. Wheel excavator:
• Wheel excavator runs on wheels and are used for
excavation and loading of dump trucks.
• most of the time it is only used for plain ground
operations.
• Because of wheel, it is not suitable for hilly areas due to
low grip value to the ground.
• Far more unusual than Crawler Excavator, Wheel
Excavator provides greater road mobility and do not
requires extra equipment (Truck and Trailer) to be
moved. 15

16. 2. Wheel excavator
• Tracks absence do not allow it to work on difficult
terrains, but Wheel Excavator make good impression for
duties related to roads or made on flat grounds.
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17. Components of excavator

18. Structures: It supports the weight of the machine,
provide traction on unstable surfaces such as mud and
allow the machine to move.

19. Hoe
• The hoe is made of three strong members;
Boom
Dipper arm
Bucket
• This structures are hinged to each other and the
boom is hinged to the revolving unit.
• Movement of each hinge is controlled by two way
hydraulic cylinders.
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20. Booms and Sticks
• Is a large hydraulically-articulated.
• Operators fit different tools to the arm depending on the job.
• These tools include buckets, claws, thumbs, jackhammers,
grapples, compactions wheels, tree shears and other tools
specific to certain industries

21. Buckets: -
• Excavator buckets are made of solid steel and generally contains
teeth protruding from the cutting edge, to disrupt hard material
and avoid wear-and-tear of the bucket
•General Purpose (GP) buckets are best for digging in soft to
hard ground with low to moderate abrasive materials.

22. The house:
• It is a component pivot above the under carriage.
• The pivot allows it to rotate 360 degrees.
• The engine, cab and the boom are all mounted on the house.
• Modern excavators can be equipped with tightly sealed cabins for
noise and dust control, heated seats and ergonomic controls.

23. Arm :-is a part of excavator which receive mechanical
work from boom stick and transfer to the bucket by a
means of mechanical linkage and hydraulic cylinder.

24. Arm cylinder: is a hydraulic cylinder which is used to
actuate the arm of excavator.

25. Boom cylinder: used to move the boom stick at an
angle

26. Hydraulic system of excavator
• The hydraulic system of an excavator transmits
hydraulic flow generated by a hydraulic pump to a
working part through hydraulic oil.
• Hydraulic system (i.e. hydraulic cylinder, fluids pistons
and hose) are responsible for generating and regulating
movements of an excavator’s structural parts.

27. Hydraulic system of excavator
Hydraulic system consists of
1. control valves: used to control overall hydraulic system
I. directional control valve
II. flow control valve
III. check valve
IV. pressure relief valve
V. counter balance cheek valve

28. Hydraulic system of excavator
2. Hydraulic cylinder: used to actuate the incoming pressurized fluid to
mechanical work.
3. Reservoir: The hydraulic fluid reservoir holds excess hydraulic fluid to
accommodate volume changes from cylinder extension and contraction.
4. Hydraulic pump: used to pressurize the fluid before it enters to hydraulic
cylinder.
5. Hydraulic motor:-used as a power source for hydraulic pump.
6. Hydraulic fluid: fluid used in hydraulic system.
7. Filters: are an important part of hydraulic systems. Metal particles are
continually produced by mechanical components and need to be removed
along with other contaminants.
8. Hose:- used as a passage for hydraulic fluids

29. Hydraulic system of excavator
Figure: hydraulic system

30. 30

31. Actuators
• hydraulic actuator consists of
cylinder or fluid motor that uses
hydraulic power to facilitate
mechanical operation.
• The mechanical motion gives an
output in terms of linear, rotary
or oscillatory motion.
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32. Swing motor
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33. Main Components
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34. Engine
Caterpillar 324D excavator engine
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35. Undercarriage
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36. Specifications of excavators
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37. Dimensions
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