When trenchers were first introduced to the residential
and commercial contractors, they rapidly became the
backbone of the crew. The time and labor trenchers
saved when they replaced the pick and shovel was
simply incredible. The contractor was able to double
the number of jobs his crew could complete in the
same amount of time – or less.

The standard types of trenchers, whether dedicated
units or attachments, they are versatile machines
for contractors to have with them on the job. They
can be used for many different purposes, from digging
valve box holes to trenches for drain pipes. In
areas that contain rocky soil, large roots, or
other problems where the other machinery can’t access
the soil, the trencher will minimize downtime that
was once spent digging by hand.

The many types of vibratory plows will offer even
more labor saving options. These plows eliminate
the hand labor of having to lay the pipe and
backfilling on numerous jobs. Even though vibratory
plows have taken their market share and are great
for pulling pipe, trenchers are still very important
for many different types of applications.

The impressive company Bobcat offers three different
trenching attachments that are designed for use on
the smaller skid steer loaders. The attachment
models LT102, LT203, and LT304 all have digging
depths from 2 – 4 feet.

Mini trenchers
The mini trenchers have been re-designed and
finely tuned from the same concept that made standard
trenchers so popular. As the name suggests, they
are lightweight, with the largest models weighing
less than 400 pounds. They are also compact,
allowing you to put them in the back of an average
pickup truck.

They will also dig a trench around 4 inches wide,
and up to 13 inches deep, neatly laying the soil
on side of the trench. Without any trouble at
all, you can cover pipe with the backfill, leaving
a barely visible seam in the soil.

With time being money, these types of mini trenchers
are the answer when working in tight or small areas,
or on jobs that have a lot of trees or shrubbery.
Mini trenchers have a turning radius of less than
two feet and they will easily fit through most
garden gates. Jobs that would normally need a lot
of manual labor will now save you a lot of time
and man power.

If you do construction or excavation work, even
gardening, you’ll find trenching and plowing
equipment to be essential to your work. If you’ve
never used these types of equipment before,
you’ll be amazed at just how much time you can
save.

If you are just starting up your business, you’ll
find this type of equipment to be just what you
need. You won’t need a lot of labor with a trencher,
as you can do most of it yourself. For saving
time, money, and effort, trenching and plowing
equipment is the way to go.

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Digging trenches is one of the oldest types of work
with both construction and excavating. Prior to World
War 2, trenches were dug by hand. As workers dug the
trenches deeper, the sides needed to be shored or
supported, to keep the walls of the trench from caving
in.

Following the World War, several innovations were made
in backhoes, and trench digging seemed to fade away
as a profession. By 1950, hydraulically actuated
backhoes were developed, which make it possible to
rapidly dig very deep trenches. Resulting from the
innovations with backhoes, and because there were no
workers inside digging the trenches, the walls no
longer needed to be shored.

All types of trenches have what’s known as a stand up
time. This time is the amount of time that elapses
from the time the ditch is dug until the time the
trench walls start to collapse. The stand up time
is dependant on many factors, which include the type
of soil, water content, trench depth, weather
conditions, and whether or not the soil has been
disturbed.

The stand up time can be as short as zero seconds
or as long as several months, as they are very
difficult to predict. Before the trench can be dug,
someone must take soil samples as way of estimating
the stand up time. Keep in mind that the soil
conditions can be dramatically different only a
few feet from where the sample of the soil was taken.

After the trench has been dug, workers will go down
into the trench, and perform whatever work is
needed, such as laying pipe or installing telephone
lines, welding pipe, or installing valves. If the
trench walls aren’t supported, there is the possibility
of the walls collapsing and trapping the workers in
the trench. Throughout history, there have been
100 – 300 people killed in the U.S. each year
due to trenches collapsing.

The public has become very aware that industrial
progress will often have negative side effects as
well. The place of engineers protecting the
public from these types of side effects is a very
controversial issue. The use of trench boxes on
the site, will help to ease this debate.

The trench box, also called a trench shield, may
be placed in the trench to prevent failures from
injuring workers. The trench box consists of two
large plates, normally made from steel, which are
parallel to the walls of the trench, and horizontal
cross members which will hold the two plates
apart.

The lower edge of the trench box rests at the
bottom of the trench, with the top edge of the
box extending above the top of the trench. The
workers will stay between the plates of the trench
box, so that if the trench does collapse, the dirt
will be stopped by the outside of the trench box.
As the work progresses, the trench box is pulled
along in the trench with a backhoe or other machine.

When a project calls for a large excavation such
as digging the foundation for a tall building, the
supporting structure for the excavated walls will
be specified in the plans. The big problem with
not using trench boxes occurs in cities, when
water or sewer lines are being installed or
repaired. The engineer doesn’t specify for the
trench box in the plans, but instead leaves it
up to the contractor.

Anytime you are going to be digging trenches or
working in them, you should always use common sense
and take your time. Trenches can be very deadly,
especially if trench boxes aren’t used. To be on
the safe side, you should always use a trench box
if you need to be in the trench. If you don’t
need to be in the trench – do the smart thing
and let the machines do all of the work.

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The skid loader is a rigid frame, engine powered
machine with lift arms that are used to attach a
wide variety of labor saving tools or attachments.
Skid loaders are normally four wheel drive with
left side drive wheels that are independent of
right side drive wheels. With each side being
independent to the other, the wheel speed and
direction of rotation of the wheels will determine
which direction the loader turns.

Skid loaders are capable of turning in their own
tracks, which makes them very maneuverable and
valuable for jobs that require the use of compact,
agile loader.

Unlike conventional front loaders, the lift arms
lay beside the driver with the major pivot points
located behind the shoulders of the operator. Due
to the operator being in close proximity to moving
booms and buckets, earlier models of skid loaders
weren’t as safe as conventional front loaders,
particularly during entering and exiting.

Skid loaders today have fully enclosed cabs and
other safety features that will protect the operator
from injury. Just like other front loaders,
the skid steer can scrape material from one
location to another, carry material in a bucket,
or load material on a truck or a trailer.

Operation
A skid loader can sometimes take the place of a
large excavator by digging a hole out from the
inside. The skid loader will first dig a ramp
that leads to the edge of the hole. Then, the
loader will use the ramp to carry material out
of the hole.

The skid loader will then reshape the ramp by
making it steeper and longer as the excavation
gets deeper. This method is very useful for
digging under an overhead structure where the
overhead clearance doesn’t allow for the boom of
a large excavator, such as those situations where
you are digging a basement under a house.

The bucket of most types of skid loaders can be
replaced with several specialized buckets or
attachments, many of which are powered by the
hydraulic system of the loader.

History
The first 3 wheeled front end loader was invented
by two brothers, Cyril and Louis Keller in their
machinist shop in Minnesota back in 1957. The
Kellers built the loader to help a nearby farmer
clean turkey manure from his two story barn. The
light and compact loader, with the rear caster
wheel, was able to turn around within the length
of itself, while performing the very same tasks as
conventional front end loaders.

Down the road, the Melroe manufacturing company
in Gwinner ND, purchased the rights to the Keller
loader in 1958 and hired the brothers to continue
their loader invention. Resulting from the
partnership, the M-200 self propelled loader was
introduced at the end of 1958.

The loader featured two independent front drive
wheels and a rear caster wheel, a 12.9 engine and
a 750 lb lift capacity. Two years later, they
ended up replacing the caster wheel with a rear
axle and introduced the M-400 loader, which was
the first four wheel skid steer loader in the
world.

In 1962, the Bobcat name was added to describe
the key features of the machine – touch, agile, and
quick. The M-440 was powered by a 15.5 HP engine
and offered a 1100 lb rated operating capacity.
In the mid 1960s, the skid steer loader progressed
with the introduction of the M600 loader.

Years later, the Bobcat skid steer loader experienced
quite a few changes, including the development of
a hydrostatic drive system, enforced cab structures,
radius and vertical lift arm configurations,
deluxe instrumentation, and even heating and air
conditioning.

In addition to the rubber tire skid loaders of today,
there are now all-wheel steer loaders and even
compact track loaders. Compact track loads offer
less ground disturbance and feature better traction
and control in soft, muddy, wet, and even sandy
ground conditions.

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There are always going to be times when, no matter
how carefully an excavation company plans out a
project, there simply isn’t enough equipment on hand
to handle the requirements of the project without
running out of time. The choices at this point are
clear – rent the machines you need or go ahead and
make the purchase.

It is however, not easy to make these types of
decisions, thanks to several factors that you’ll
need to consider.

Rental pricing
Its no secret that rental companies make a killing
with the equipment they rent out. Most companies
will rent on a daily or weekly basis, which is good
for them but can be bad for you. Depending on what
area you work in, the price can be very high or
just right.

Depending on what type of equipment you need, the
price to rent will vary. Excavators and off road
dump trucks are among the highest to rent, as they
can cost as much as 12,000 dollars per month! This
may seem a bit outrageous at first, although if you
own a profitable company and are working on a big
project, you’ll have problems meeting the price.

Buying
When you need more equipment and don’t want to rent,
you can buy your equipment. Buying is the way to
go if you plan on using the equipment more. If you
work on large projects on a frequent basis, you may
want to look into buying the equipment you need
instead of renting.

Buying will save you money in the long run, providing
you are going to be using the equipment again. If
you need the equipment for one or two projects, you
may just want to rent. Sure you won’t own the
equipment, although you certainly don’t want to buy
something you won’t be using.

Servicing
One of the great things about renting is the fact
that company you rent from is responsible for fixing
anything that breaks. Your company won’t be responsible
for repairs, as you don’t own the equipment. If
something breaks or goes wrong, simply call the
company and they will come out there and fix the
problem, as the price for repair is included in the
rental contract.

If you choose to go ahead and buy the equipment,
then your company will be responsible for the repair
of the equipment. As you probably know with owning
other equipment, you’ll need to do regular maintenance
and service on the equipment.

Making that final choice on renting or buying is
ultimately up to you. You should always think about
finances, and if you can afford the machinery. If
you don’t have the finances or capital to buy what
you need, you should go with renting. Either way
you go, you’ll get the machines you need to complete
your job and stay ahead of schedule.

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A skid steer loader with backhoe attachment or a backhoe
loader in general can be very productive if it is
operated safely and efficiently. The best way to
get the job done safely and efficiently is to know
yourself, the job site, and your equipment.

Even though the models of backhoes will vary, there
are safety features with all of them that include
steps and grab handles for getting on and off of
the machine. Backhoes also feature frame lock levers
and attaching levers to keep the backhoe securely
fastened to the loader frame during operation as well
as transporting.

In addition to these standard safety features, there
are some backhoes that provide a safety chain. The
safety chain will prevent the backhoe mounting
frame from rotating backwards and unexpectedly
trapping the operator, which can result in serious
injury or death. Therefore, it is always important
to know and check all of the mounting and attachment
points and the safety chain before you operate the
backhoe.

If you’ve attached the backhoe to the loader, you
should take a moment to inspect it and perform any
necessary maintenance. Check for broken or
damaged parts, also making sure to check for leaks,
cracks, excessive wear, and check the control
levers.

The warning and safety signs and instructional
decals are very important and will help you to
avoid injury. You should always take them seriously
and replace any damaged or missing decals.

Every 8 hours or so, you should grease all of the
zerk fittings, and check the hydraulic fluid
and oil and a daily basis. If the fluid is low,
the backhoe will not operate. Therefore, you
should always take the time to check your machine.

Anytime you have to leave the operator seat of the
backhoe, you should lower the bucket or attachment
to the ground, turn the engine off, remove the
ignition key, then exit the machine.

When the time comes to drive to the next job site,
you should always make sure that you have fully
raised both the front and rear stabilizers and
make sure you’ve put the backhoe seat into the
“down” position for better visibility. Before
you drive off, make sure that you’ve installed the
transport locking pin.

Here are some other things to keep in mind:
- Always select the right size bucket for
the job.
- Stake out the work area that is going to
be excavated and use flags to mark the area.
- Never work in areas that have inadequate
overhead clearances.

Always make sure that you keep bystanders or other
workers out of the swing area. If anyone gets in
the way of the boom swinging, they can very easily
get injured. The machine has no feelings,
therefore you should always be aware of who is
around you and where they are standing.

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Hydraulic machinery are machines and tools that use
fluid power to do the work. Almost all types of
heavy equipment is a common example. With this type
of equipment, hydraulic fluid is pumped to a high
pressure then transmitted through the machine to
various actuators.

The hydraulic pumps are powered by engines or electric
motors. The pressurized fluid is controlled by the
operator with control valves and then distributed
through hoses and tubes.

The increasing popularity of hydraulic machinery is
due to the large amount of power that is transferred
through small tubes and flexible hoses. The high
power density and wide array of actuators can make
use of this power.

Hydraulic power
The theory that lies behind hydraulic equipment is
fluid pressure.
1. A force that acts on a small area can
create a bigger force by acting on a larger area
by hydrostatic pressure.
2. A large amount of energy can be carried
by a small flow of highly pressurized fluid.

Pumps
A hydraulic pump will supply the fluid to the
components in the system. Pressure in the system
will develop in reaction to the load. Pumps have
a power density of around ten times greater than
an electric motor. The pumps are powered by an
electric motor or engine, which is connected through
gears, belts, or a flexible elastomeric coupling
to reduce the heavy vibration.

The common types of hydraulic pumps for hydraulic
machinery applications include:
1. Gear pump – the gear pump is cheap,
durable, and simple. It is less efficient, simply
because it is constant displacement and suitable
for pressures that are below 3,000 psi.
2. Vane pump – vane pumps are cheap, simple,
and reliable. They are good pumps for higher flow
low pressure output.

Hoses and tubes
A hydraulic hose is graded by pressure, temperature,
and compatibility of fluid. A rubber interior is
surrounded by multiple layers of woven wire and
rubber. The exterior of the hose is designed for
resistance against abrasion.

The bending radius of the hydraulic hose is
designed very carefully into the machine, since
a hose failure can be deadly, and violating the
minimum bend radius of the hose can also cause
failure.

A hydraulic pipe is thick enough to have threads
cut into it for connections. It’s rarely used
for high pressure systems though, which prefer to
have tubes or hoses. The pipe itself lends to
weldings and can also be used to fabricate the
manifold.

Hydraulic pipes on the other hand are preferred
over hoses whenever possible, as they are simply
more durable. Tubes are also preferred over pipes,
as they weigh a lot less. Hydraulic tubes will
normally have flared ends and captive nuts to
make connections. They can also be steel welded
with floating nuts and face seal fittings on the
ends.

Both tubes and pipes for hydraulic applications
traditionally haven’t been plated or painted,
since the temperature and oil they operate under
drive away moisture and reduce the risk of rust.

Fittings
The fittings with hydraulic machinery serve
several purposes:
1. To bride different standards, such
as the O-ring boss to JIC or pipe threads to the
face seal.
2. Allows proper orientation of
components, as a 45 or 90 degree, straight, or
even swivel fitting will be chosen as it is
needed. They are designed to be positioned in
the correct orientation and then tightened as
needed.
3. To incorporate bulkhead hardware.
4. A quick disconnect fitting may be
added to a machine without having to modify hoses
or valves.

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There are many different opinions as to what
machines should actually be classified as earth
moving equipment. There are many different types
of equipment that fall in this category, such as
excavators, backhoe loaders, dump trucks, and
even loaders.

Other machinery that falls in between are articulated
trucks, wheel and track tractors, and even
scrapers. The thin line is normally drawn at
motor grades, which are more than capable or light
duty excavation, although they are mainly used
to level lots and grade roads.

If you take a glance at any equipment literature
from leading companies such as CAT, Komatsu, or
Case, you’ll see right away that they believe the
biggest and most important change over the last
several years is increased productivity. This is
normally followed by greater comfort and safety.

The increase in productivity is the result of
many different advancements. CAT (Caterpillar)
cites that more powerful engines with a faster
rise in torque which allows machines to respond
faster to increased power demands. Even though
this new generation is far more powerful, it
has a reduced impact on the environment as well.

Electronics
Most of the newer machines have electronic
control systems that will optimize both engine
and transmission performance, as well as fuel
consumption and hydraulic system performance.

Take for example the CAT mid sized G series
wheel loaders that feature electronically controlled
powershift transmissions. Each and every
transmission offers autoshift capabilities that
ease the pressure on the operator, and an
electronic clutch pressure control that smooth
shifts the gears for longer life.

Comfort
In the industry, good operators are getting harder
and harder to find. Manufacturers find themselves
stressing that operator comfort and convenience
need to be taken into account not only to make
the job easier, but also more efficient and
productive as well.

The new cab designs offer better visibility,
reduced noise and vibration, and improved comfort
as well. The new control systems will require low
operator effort while also improving the control
of the machine for both the experienced as well
as the in-experienced operator.

Easier maintenance
Almost all new machinery offers electronic
monitoring systems that will provide constant
information on the health of the machine for the
operator. These types of systems provide information
to technicians, including service modes that will
help them to diagnose conditions quickly.

Now days, machines are designed to make routine
maintenance easier. With CAT’s wheel loaders,
regular service points are easy to access from
ground level, with site gauges making it easier
to check the fluid of the radiator, hydraulic oil,
and transmission – without having to use dipsticks.

Changes for the better
If you compare the excavation equipment of today
with the machines of the past, you’ll notice that
the changes are better. The machines of the past
relied more on operator skill and technique, as
very few of them had electronic features.

Today, almost all types of heavy machinery offer
electronic features. Electronics are a great
thing, as they can make the life of an operator
easier than ever. You don’t need to get out and
check the fluids anymore, as all you need to do
is take a look at your instrument panel, which can
help to save you a lot of time.

Operators who have a lot of experience know first
hand that machines of the past can’t begin to
compete with machines of today. With technology
always getting better, it just makes you wonder
what is in the future for heavy machinery. Years
from now, one can only begin to wonder just great
heavy machinery will get – and what other features
will make the life of an operator even easier than
it is now.

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Also referred to as a loader backhoe, the backhoe
loader is an engineering and excavation vehicle that
consists of a tractor, front shovel and bucket and
a small backhoe in the rear end. Due to the small
size and versatility, backhoe loaders are common
with small construction projects and excavation type
work.

Originally invented in Burlington Iowa back in 1857,
the backhoe loader is the most common variation of
the classic farm tractor. As the name implies, it
has a loader assembly on the front and a backhoe
attachment on the back.

Anytime the loader and backhoe are attached it is
never referred to as a tractor, as it is not normally
used for towing and doesn’t normally have a PTO.
When the backhoe is permanently attached, the
machine will normally have a seat that can swivel
to the rear to face the backhoe controls. Any type
of removable backhoe attachments will normally have
a seperate seat on the attachment itself.

Backhoe loaders are common and can be used for many
tasks, which include construction, light transportation
of materials, powering building equipment, digging
holes and excavating, breaking asphalt, and even
paving roads.

You can often replace the backhoe bucket with
other tools such as a breaker for breaking and
smashing concrete and rock. There are some loader
buckets that offer a retractable bottom, which
enable it to empty the load more quickly and
efficiently.

The retractable bottom loader buckets are often
times used for grading and scratching off sand.
The front assembly on a backhoe may be either
removable or permanently attached. Often times,
the bucket can be replaced with other tools or
devices. In order to mount different attachments
to the loader, it must be equipped with a tool
coupler. The coupler consists of two hydraulic
cylinders on the end of the arm assembly, which
can expand and retract to allow different tools to
be attached to the unit.

There are several types of backhoe loader brands,
including New Holland, John Deere, and Case. Some
will offer you cabs, while others won’t. The
newer types of backhoe loaders even offer you air
conditioning, radios, and other accessories that
make you feel like you are working with luxury.

Common with excavating jobs, the backhoe can serve
many purposes. It can haul equipment and supplies
in the loader bucket. Another great use is to cover
up dirt when filling in trench lines or covering
up pipe that was just put in the ground. The
backhoe attachment at the rear is ideal for digging
water pipes and sewer pipes.

The best thing about the backhoe loader is the
fact that they are easy to operate. You don’t
need to be a rocket scientist to fully operate this
nifty piece of equipment.

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The harvester is a type of heavy machinery that is
employed in cut to length logging operations for
felling, buckling, and cutting up trees. Normally,
a harvester is employed alongside a forward that
will haul the logs and trees to a roadside landing.

Harvesters were developed in Sweden and Finland,
and today they do nearly all of the commercial
felling in these countries. They work best for
less difficult terrain for the clear cutting area
of forest. For steep hills or removing individual
trees, chain saws are normally preferred. In
the nordic countries, small and agile harvesters
are used for thinning operations and manual cutting
is only used during extreme conditions or by self
employed owners of the forest or wooded area.

The leading manufacturers of harvesters include
Timberjack (which is owned by John Deere) and
Valmet, which is owned by Komatsu.

Normally, harvesters are built on a robust all
terrain vehicle, which can either be wheeled or
tracked. Sometimes, the vehicle can be articulated
to provide tight turning around obstacles. A
diesel engine will provide power for both the
vehicle and the harvesting mechanism through a
hydraulic drive.

An articulated, extensible boom that is similiar
to that of an excavator, will reach out from the
vehicle to carry the head of the harvester. There
are even some commercial harvesters that are
adaptations of excavators with a new harvester
head, while the others are purpose built vehicles.

The normal harvester head may consist of:
1. A chain saw to cut the tree at the
base and also to cut it to length. The saw is
hydraulically powered rather than using a 2 stroke
engine of a portable version. It offers a more
robust chain and a higher output power than any
saw carried by man.
2. Two curved de-limbing knives that can
reach around the trunk to remove branches.
3. Two feed rollers to reach out and grasp
the tree. The wheels will pivot apart to allow
the tree to be embraced by the head of the harvester,
and pivot together to hug the tree tight.
4. Two more curved knives for de-limbing.

All of this is controlled by an operator who sits
in the cab of the vehicle. A control computer is
used to simplify mechanical movements and keep the
length and diameter of trees that have been cut.

The length is computed by counting the rotations
of the gripping wheels. The diameter is computed
from the pivot angle of the gripping wheels that
hug the tree.

Harvesters are normally available for cutting trees
up to 900 mm in diameter, built on vehicles that
weight up to 20 t, with a boom that reaches up to
a 10m radius. The larger, more heavier vehicles
do more damage to the forest, although a longer
reach will help by allowing more trees to be
harvested with less movements required by the
vehicle.

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The bulldozer is a very powerful crawler that is
equipped with a blade. The term bulldozer is often
used to mean any type of heavy machinery, although
the term actually refers to a tractor that is fitted
with a dozer blade.

Often times, bulldozers are large and extremely
powerful tracked vehicles. The tracks give them
amazing ground mobility and hold through very rough
terrain. Wide tracks on the other hand, help to
distribute the weight of the dozer over large areas,
therefore preventing it from sinking into sandy or
muddy ground.

Bulldozers have great ground hold and a torque
divider that’s designed to convert the power of the
engine into dragging ability, which allows it to
use its own weight to push heavy objects and even
remove things from the ground. Take the Caterpillar
D9 for example, it can easily tow tanks that weight
more than 70 tons. Due to these attributes,
bulldozers are used to clear obstacles, shrubbery,
and remains of structures and buildings.

The blade
The blade on a bulldozer is the heavy piece of
metal plate that is installed on the front. The
blade pushes things around. Normally, the blade
comes in 3 varieties:
1. A straight blade that is short and has
no lateral curve, no side wings, and can be used
only for fine grading.
2. A universal blade, or U blade, which is
tall and very curved, and features large side wings
to carry more material around.
3. A combination blade that is shorter,
offers less curvature, and smaller side wings.

Modifications
Over time, bulldozers have been modified to evolve
into new machines that are capable of things the
original bulldozers weren’t. A good example is
that loader tractors were created by removing the
blade and substituting a large volume bucket
and hydraulic arms which will raise and lower the
bucket, therefore making it useful for scooping
up the earth and loading it into trucks.

Other modifications to the original bulldozer
include making it smaller to where it can operate
in small working areas where movement is very
limited, such as mining caves and tunnels. Very
small bulldozers are known as calfdozers.

History
The first types of bulldozers were adapted from
farm tractors that were used to plough fields. In
order to dig canals, raise earth dams, and partake
in earthmoving jobs, the tractors were equipped
with a thick metal plate in the front. Later
on, this thick metal plate earned the name blade.

The blade of the bulldozer peels layers of soil
and pushes it forward as the tractor advances.
The blade is the heart and soul of the bulldozer,
as it was the first accessory to make full use
for excavation type jobs.

As the years went by, when engineers needed
equipment to complete larger jobs, companies such
as CAT, Komatsu, John Deere, Case, and JCB started
to manufacture large tracked earthmoving equipment.
They were very loud, very large, and very powerful
and therefore earned the nickname “bulldozer”.

Over the years, the bulldozers got bigger, more
powerful, and even more sophisticated. The
important improvements include better engines,
more reliable drive trains, better tracks, and
even hydraulic arms that will enable more precise
manipulation of the blade and automated controls.
As an added option, bulldozers can come equipped
with a rear ripping claw to break up pavement or
loosen rocky soil.

The best known manufacturer of bulldozer is CAT,
which has earned a vast reputation for making
tough and durable, yet reliable machines. Even
though the bulldozer started off a modified farm
tractor, it rapidly became one of the most useful
pieces of equipment with excavating and construction.

PPPPP

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