Bulldozers are large, tracked heavy equipment vehicles equipped with a metal blade used to push soil, sand, rubble and debris. They have excellent mobility over rough terrain thanks to their continuous tracks. The primary tools of a bulldozer are the blade, used to push material, and the ripper, a claw-like device used to break up compacted materials. Bulldozers are commonly used in construction, mining, forestry and other industries for earthmoving tasks.

2.  A bulldozer is a crawler (continuous
tracked tractor) equipped with a substantial
metal plate (known as a blade) used to push
large quantities of soil, sand, rubble, or other
such material during construction or conversion
work and typically equipped at the rear with a
claw-like device (known as a ripper) to loosen
densely compacted materials.
 A bulldozer is a crawler (Continuous tracked
tractor) used to push large quantities of soil,
sand, rubble, during construction work.

3. • The term “bulldozer” is often used to mean any heavy
equipment (sometimes a loader and sometimes an
excavator), but precisely, the term refers only to a
tractor fitted with a dozer blade.
 The bulldozer's primary tools are
the blade and the ripper.
 Dozers, tractors
equipped with a blade
are standard equipment
for excavating.

4.  The first bulldozers were adapted from Holt farm tractors
that were used to plough fields. The versatility of the
bulldozers in soft ground for logging and road building led
directly to their becoming the armored tank in World War I.
In 1923, a young farmer
named James Cummings and
a draftsman named J. Earl
McLeod made the first
designs for a bulldozer. A
replica is on display at the
city park in Morrowville,
Kansas where the two built
the first bulldozer.

5.  Bulldozers can be found on a wide range of
sites, mines and quarries, military bases, heavy
industry factories, engineering projects and farms.
 The tracks give them excellent ground holding
capability and mobility through very rough terrain.
Wide tracks help distribute the bulldozer's weight
over a large area (decreasing ground pressure), thus
preventing it from sinking
in sandy or muddy ground. Extra wide tracks are
known as swamp tracks or LGP (low ground
pressure) tracks. Bulldozers have transmission
systems designed to take advantage of the track
system and provide excellent tractive force.
 Most often, bulldozers are large and powerful tracked heavy equipment.
The tracks give them excellent ground hold and mobility through very
rough terrain.
 Wide tracks help distribute the bulldozer's weight over a large area thus
preventing it from sinking in sandy or muddy ground.
The bulldozer's primary tools are the blade and the ripper.

6. Bulldozer
Sketch

8.  The bulldozer blade is a heavy metal plate on
the front of the tractor, used to push objects,
and shove sand, soil and debris.
 Three Types:
1. A straight blade ("S blade") which is short and has no
lateral curve and no side wings and can be used for
fine grading.
2. A universal blade ("U blade") which is tall and very
curved, and has large side wings to carry more
material.
3. An "S-U" combination blade which is shorter, has less
curvature, and smaller side wings. This blade is
typically used for pushing piles of large rocks, such as
at a quarry.

9.  The ripper is the long claw-like device on the back of the
bulldozer. Rippers can come as a single (single shank/giant
ripper) or in groups of two or more (multi shank rippers).
 Usually, a single shank is preferred for heavy ripping. The
ripper shank is fitted with a replaceable tungsten steel alloy
tip
Ripping rock lets the ground surface rock
be broken into small rubble easy to handle
and transport, which can then be removed
so grading can take place.
Agricultural ripping lets rocky or very hard
earth be broken up so otherwise unploughable
land can be farmed.

10. For example, much of the best land in the
California wine country consists of old lava flows.
With heavy bulldozers the lava is shattered,
allowing agriculture.
 Also, hard earth can be ripped and broken up to
allow planting of orchards where trees could not
otherwise grow.

11.  Moisture Content –
1. Moisture falls below the optimum moisture content value,
particles will adhere to each other and more – effect – it make it
diffcult to break material out of its natural state.
2. If moisture content increases above the optimum, material
becomes heavy and will have a negative effect on dozeing
performance.
 Particle size -
1. Specific size of material has a direct bearing on the ability of
dozer blade to penetrate and loosen materials. Large particles
resist penetration more than smaller ones, requires more dozing
power.
2. Sharp-edged particles exert more force against the curl
movement of blade. Material consisting of irregularly and sharp-
edged particles is more difficult to doze than material
composed of round-edged particles.
 Voids –
 1. More force is required to break up the tightly bonded
materials. Also such materials is generally heavy, making
additional demands on the available horse power of the dozer.

12. In military use, dozer blades are fixed on combat
engineering vehicles and can optionally be fitted
on other vehicles, such as artillery tractors like
the Type 73 or M8 Tractor.
 Dozer blades can also be mounted on Main
battle tanks, where it can be used to clear
antitank obstacles, mines, and dig improvised
shelters.
Combat applications for dozer blades include
clearing battlefield obstacles and preparing fire
positions.

13.  Bulldozers are large and heavy vehicles
making them a good choice for demolition
and clearing sites.
 Caterpillar tracks give bulldozers a distinct
advantage allowing them to be surprisingly
maneuverable for their extreme weight.
 The tracks are also quite wide which helps to
distribute their heavy weight preventing them
from sinking in sandy or muddy ground.

14.  Bulldozers are renowned for holding their
ground which gives them phenomenal strength
for pushing and dragging obstructions in their
path.
 Some models of tanks can even tow up to 70
tons of weight and are used for moving written
off vehicles and military purposes as well as in
construction and demolition projects.

15.  Bulldozers are often used in road building,
construction, mining, forestry, land clearing,
infrastructure development, and any other
projects requiring highly mobile, powerful, and
stable earth-moving equipment.
 The bottom edge of the blade can be
sharpened, e.g. to cut tree stumps.

16.  Loads – Fully heaped blade
 Engine Speed – Full rpm / full capacity
 Travel – 1 to 8 km/hr,
haul distance- 60 to 90m etc.
 Spreading – Time being wasted?
 Mechanical – All adjustment to power unit
maintained
 General – Right machine for job?
Right operator?
Right procedure?
Machine proper maintained?