Earthmoving equipment encompasses a variety of machines used for tasks such as excavation, grading, and material handling in construction. Crawler loaders, a fusion of excavators and backhoes, offer stability and versatility for small projects, evolving significantly from their early design in the 1920s to modern hydraulic systems. The document details the advantages, history, and applications of these machines, highlighting their operational efficiency compared to wheeled loaders.

1. EARTHMOVING EQUIPMENT
CRAWLER LOADERS
Anoushka Shome | 1DT16AT005

2. EARTH MOVING EQUIPMENTS
Earth-moving equipment covers a broad range of machines that can excavate and grade soil and rock, along
with other jobs. Earth movers and other heavy equipment help to speed not only earth work but also materials
handling, demolition, and construction. They are used for a wide range of earthworks including laying
foundations, grading soil, removing dirt and rocks, digging trenches, demolition works, etc.
These complex machines are operated by professionals. Many types of heavy construction equipment are
designed for multiple functions, making them indispensable on job sites.

3. Different types of earth-moving machines are capable of accomplishing different types of tasks
and owing to technological advancements in the industry, today there are various types of earth-
moving machinery available in the market capable of catering to almost any kind of construction
activity.
Some of the most prominently used earth-moving equipment in the construction industry:
• Excavators
• Backhoe Loaders
• Bulldozers
• Skid-Steer Loaders
• Trenchers
• Track/crawler Loaders

4. THE DIFFERENT TYPES OF LOADERS USED IN CONSTRUCTION
Backhoe: A compact machine consisting of a loader shovel or bucket on the front and backhoe boom with
an attachment on the back, these highly productive machines are capable of digging, trenching, back-
filling and material handling in an extensive range of applications.
Multi-terrain: Designed to deliver extremely low ground pressure and features a rubber track system
capable of traveling over challenging terrains and underfoot conditions. Benefits include exceptional
flotation, traction and stability for the flexibility to work in all different types of material handling task and
environments.
Skid steer: Available as a crawler or four-wheel-drive machine, skid steer loaders feature a unique lift-arm
design and sturdy, rigid frame to deliver exceptional power in a small package. Skid steers are used in
agriculture, construction, landscaping, road work and many other industries that benefit from its efficiency
and versatility switching between work tools and attachments.
Track-type: Among the most powerful and durable types of loaders in construction, tracked models are
utilized in the toughest jobs and most rugged ground conditions. The stability of the tracked chassis is ideal
for working on uneven terrains, while the power generated from the hydraulic system provides high-output
digging and earthmoving on hard ground. You’ll find a broad range of sizes and configurations of track
loaders, including ship-hold, port handling and waste handler models.

5. CRAWLER LOADERS
A crawler loader is a cross between an excavator and a backhoe or bucket loader. Its tracks give
it excellent stability, and its versatile bucket makes it useful for moving soil and debris and for loading
material onto trucks. Crawler loaders are also used for excavation on relatively small projects. For larger-
scale work, a hydraulic excavator is often used instead of a crawler loader.

6. History of Crawler Loaders
The history of tracked loaders can be traced to the 1920s, when tractors were fitted with buckets that could
be used for handling materials. Then in the 1930s, an English company, E. Boydell, created a small loader that
included a tractor and a small bucket.
The first versions, made from track tractors
with scratch-built loaders, were cable-
operated like the bulldozers of that time.
Both the loaders and the dozers lacked
the ability to dig into hard ground but
worked well when performing tasks like
moving materials and loading duties, such
as railroad cars and trucks.
Hydraulic systems brought a major change
for tracked loaders, increasing the power
of the machine and allowing the
application of down pressure to the
bucket, which made it much easier to dig
unworked ground with them.
The next major change was the addition
of hydrostatic drive systems.
An early model (First Tractor Company) tractor, still
operational, in Xinbu Island, Hainan Province, China.

7. It is noted that one of the first companies to design crawler loader shovels was Trackson Company, which was
founded in 1922. By 1936, the company was designing tractor equipment for Caterpillar and created a
loader attachment specifically for Caterpillar tractors that had the innovation of cable-operated vertical lift
capabilities known as “Traxcavators” they were mounted above the tractor hood, which often made the
machine unstable.
The next step was to replace the cables with hydraulics, and Trackson was able to create a lighter attachment
that was well-received in the industry. In fact, Caterpillar purchased Trackson Company in 1951 and adopted
the Traxcavator name for all its crawler loaders. The company then began to build the loaders from the ground
up rather than using attachments. The first integrated hydraulic crawler loader was released by Caterpillar in
1953 and was known as the No. 6 Traxcavator. Hoover Machine Co. Ltd. and Caterpillar created an overhead
dozer that worked by excavating from the front. The material was then lifted over the top of the machine so it
could be released on the other side. For obvious reasons, overhead cab protection was a must with this design.
By the 1970s, hydrostatic motors were introduced to crawler tractors, allowing them to be controlled by using a
joystick for the tractor and another joystick for the loader. The first rear-engine hydrostatic crawler loader was
introduced in 1971 by JCB. It reportedly set the standard for future crawler loaders.
The first endless chain tread was reportedly developed by Benjamin Holt in 1904 for his steam traction engine.
Around that time, the Hornsby Company in England converted a wheeled steam traction engine to a crawler
format. This version was closer to what is known today as a bulldozer. because it was steered by controlling
power to each track. Hornsby's patents were sold to Holt about a decade later. The tracks allow the dozers to
have good ground-holding capability and mobility over even rough terrain. They are wide enough that the
weight is distributed across the machine, preventing it from sinking even when the terrain is soft. This makes
them good choices for numerous applications in construction, road building, and land clearing.

8. Tracked vehicles became common in the 1920s, such as the Caterpillar 60. They were equipped with thick metal
plates in the front to enable them to complete earth-moving tasks. By 1929, attachments included three main
types of bulldozer blades: a U-blade for pushing and carrying dirt for longer distances; a straight blade for
spreading piles of dirt; and a brush rake for brush and roots.
Over the years, dozers have been modified to fit the jobs that they are needed for. One example of this is a
smaller machine to be used in tight areas, such as in mining.
As the size of the machines grew to meet the demands of the industry, they also became more sophisticated.
This included the addition of automatic transmissions, hydraulic cylinders and electric motors, and grade control
that was automatic.

9. Uses of Crawler Loaders
The crawler loader combines the stability of the crawler tractor with the abilities of a wheel loader.
However, to construct a reliable crawler loader it requires more than simply attaching a loader bucket onto a
crawler tractor. It must be considered with its specific purpose in mind to ensure. It has the strength to survive
heavy excavating.
The introduction of hydraulic excavators reduced the market for the crawler loader because it was incapable
to match the excavator’s lifting power and flexibility.
Crawler loaders are capable of maneuvering across the entire construction site under its own power, whereas
most hydraulic excavators require towing or transport. While crawler tractors are still being manufactured
today.

10. Advantages
• Low ground pressure
• Good maneuverability in confined workspaces
• Versatility for various jobs
• High gradeability upto 30%
• Ability to work on very wet or icy ground
• Ability to work with a ripper
• Ability to work on very hot areas
The low ground pressure allows working with a crawler loader on wet and soft ground. With the LGP version
(low ground pressure) with wide track shoes the loader has less ground pressure than a child’s foot. Even on
snow and ice a tracked loader can get a good grip.
Due the hydrostatic drive the loader can turn on place. Depending on machine and bucket size a full turn in
less than 6m diameter is possible. Crawler loaders can be used to deposit material much higher than wheel
loaders or standard track excavators. The gradeability up to 30% makes it possible to amass material to little
mountains. If equipped with a ripper the machine can be used for loosening of hard soil. The penetration force
is much better than of a wheeled loader. Loading and loosening of hard material such as clay or even clinker
and compacted waste is possible.
Last but not least tracked loaders can work in hot areas such as steel mills. For some machines is a steel-mill
package available to prepare the machine for this hard job. Even for jobs in vessel discharging crawler
loaders are an appropriate tool. Late models have a bucket and loader frame kick-off function and a joystick
control. These features make working with a tracked loader very fast and effective. For forestry jobs the
machines can be equipped with a winch, for special earthmoving jobs a multi- purpose bucket (4x1) is
available.

11. Differences between Wheel and Track loaders
Wheeled loaders are lighter than track loaders making
them easier to control around jobsites and more fuel-
efficient adding value in decreased operational costs.
On the flip side, track loaders offer more operator
comfort and are often used on jobsites to increase
delivery. Track loaders are also softer on the ground
and can reduce site clean-up compared to a wheeled
loader.
Both machines do offer great maneuverability, but the
consensus upholds that wheeled loaders work best on
hard surfaces like concrete or landscaped areas while
the track loader works better in rougher conditions and
uneven terrain. Another common theme between both
track loaders and wheeled loaders is their ability to
perform multiple applications such as construction,
landscaping, excavation, and forestry. Both options use
multiple attachments to achieve many different jobs.
Ultimately, there isn’t much differentiation between
wheeled loaders and track loaders aside from the
tracks and wheels. Yet, tracks offer the added benefit
of saving contractors any downtime costs because the
tracks are designed to overcome sloppy conditions
where a skid steer would not be able to work at all.
Wheeled Loader
Track/Crawler loader

12. Manufacturing companies
Well-known dozer manufacturers include
• Caterpillar
• Komatsu
• Liebherr
• Case
• John Deere
• JCB
Liebherr 631
Caterpillar 963C
Komatsu CK35-1 John Deere 655K