Bulldozer - Icivil-Hu

BULLDOZER
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TABLE OF CONTENTS:
 Bulldozer.
 History of bulldozer.
 Types of dozers.
 Dozer uses.
 Description.
 Dozer primary tools.
 blade.
 Ripper.
 Caterpillar.
 Caterpillar d9
 Available power
 Example
 Production of dozer
 Example
 End.
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• 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 denselycompacted materials.
• The term "bulldozer" is often used erroneously to mean any heavy
equipment (sometimes a loader and sometimes an excavator), but
precisely, the term refers only to a tractor (usually tracked) fitted
with a dozer blade. That is the meaning used here
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HISTORY
• In 1923, a young farmer named James Cummings and a draftsman
named J. Earl McLeod made the first designs for the bulldozer. A
replica is on display at the city park in Morrowville, Kansas where
the two built the first bulldozer. On December 18, 1923
• Over the years, bulldozers got bigger and more powerful in
response to the demand for equipment suited for ever larger
earthworks.
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• Bulldozers can be found on a wide range of sites, mines (‫ (المناجم‬and
quarries )‫(المحاجر‬, military bases, heavy industry factories,
engineering projects and farms.
IDF Caterpillar D9R armored bulldozer
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TYPE OF DOZERS
1. Crawler (track laying) tractor.
2. Wheel type tractor.
A.Single axle.
B.Two-axle.
Single axle drive.
Two-axle drive.
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Crawler-type tractor
Wheel-type tractor
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DOZERS USES
Typical project applications are:
Land clearing.
Dozing (pushing material)
Ripping.
Towing other pieces of construction equipment's
Assisting scrapers in loading.
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DESCRIPTION
• 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 (decreasing 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 excellent ground hold and a
torque divider designed to convert the engine's power into
improved dragging ability. The Caterpillar D9, for example, can
easily tow tanks that weigh more than 70 tons. Because of these
attributes, bulldozers are used to clear areas of obstacles,
shrubbery, burnt vehicles, and remains of structures.
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THE BULLDOZER'S PRIMARY
TOOLS
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BLADES
• The bulldozer blade is a heavy metal
plate on the front of the tractor, used to
push objects, and shoving sand, soil and
debris.
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DOZER BLADES USUALLY COME IN
FOUR VARIETIES
o A straight blade ("S blade") which is short and
has no lateral curve and no side wings and can
be used for fine grading.
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• A universal blade ("U blade") which is tall and very
curved, and has large side wings to carry more
material.
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• 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.
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CUSHION DOZER BLADES
• Cushion Dozers are used to
push load scrapers or track-type tractors.
• The heavy duty design includes
a wear-resistant center liner plate and
a reinforced cutting edge section.
• Narrow width increases
maneuverability when lining up
for the next pass.
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• Blades can be fitted straight across the
frame, or at an angle, sometimes using
additional 'tilt cylinders' to vary the angle
while moving. The bottom edge of the
blade can be sharpened, e.g. to cut tree
stumps
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BLADE ADJUSTMENTS
• Tilting
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BLADE ADJUSTMENTS (CONT’D)
• Angle
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RIPPER
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• The ripper is the long claw-like device on the
back of the bulldozer. Rippers can come as a
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 breaks the ground surface rock or
pavement into small rubble easy to handle and
transport, which can then be removed so
grading can take place.
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CATERPILLAR
• The best known maker of bulldozers is probably Caterpillar in
the USA, which earned its reputation by making tough, durable,
reliable machines.
•
Komatsu, JCB and John Deere are present-day competitors.
Although these machines began as modified farm tractors, they
became the mainstay for big civil construction projects, and
found their way into use by military construction units worldwide.
The best known model, the Caterpillar D9, was also used to
clear mines and demolish enemy structures.
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• The Caterpillar D9 is a large track-type tractor designed and
manufactured by Caterpillar Inc. Though it comes in many
configurations it is usually sold as a bulldozer equipped with a
detachable large blade and a rear ripper attachment.
• The D9, with 354 kW (474 hp) of gross power and an operating
weight of 49 tons, is in the upper end (but not the heaviest), of
Caterpillar's track-type tractors, which range in size from the D3
57 kW (77 hp), 8 tons, to the D11 698 kW (935 hp), 104tons.
• The size, durability, reliability, and low operating costs have made
the D9 one of the most popular large track-type tractors in the
world.
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• Engineering Role:
Heavy bulldozer
• Propulsion: Caterpillar tracks
• Engine model:
CAT C18 ACERT (D9T)
• 3408 HEUI (D9R)
• Gross power:
464 hp (346 kW) D9T
• 474 hp (354 kW) D9R
• Flywheel power:
410 hp (306 kW) D9T
• 410 hp (306 kW) D9R
• 375 hp (280 kW) D9N
• 460 hp (343 kW) D9L
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• Drawbar pull:
71.6 tons
• Operation Weight:
108,000 lbs (48,784 kg)
• Length:
26.5 ft (8.1 m)
• Width:
14.7 ft (4.5 m) (blade)
• Height:
13 ft (4 m)
• Speed:
7.3 MPH (11.9 km/h) Forward
• 9.1 MPH (14.7 km/h) Reverse
• Blade capacity:
17.7 yd³ (13.5 m³) 9 SU blade
• 21.4 yd³ (16.4 m³) 9 U blade
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POWER AVAILABLE
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Haul
Empty
loaded
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Haul
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Haul
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Haul
Speed  9 mph
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Return
Speed  31 mph
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COEFFICIENT OF TRACTION FOR VARIOUS
SURFACES
surface
Rubber-tires
Crawler-tracks
Dry, rough concrete
0.80-1
0.45
Dry, clay
0.50-0.70
0.9
Wet, clay
0.4-0.5
0.7
Wet sand and gravel
0.3-0.4
0.35
Loose, dry sand
0.2-0.3
0.3
Dry snow
0.2
0.15-0.35
Ice
0.1
0.1-0.25
Tractive effort (usable force) = coefficient of traction x
weight
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DOZER PRODUCTIVITY
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PRODUCTION FACTORS: DOZERS
• Soil conditions
• Angle of swing
• Bucket fill
• Size
• Fill factor
• Cycle Time
• Job efficiency
•
Operator
• Site condition
• Equipment conditions
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FIGURE 107. MAXIMUM PRODUCTION RATES FOR DIFFERENT
BULLDOZERS EQUIPPED WITH STRAIGHT BLADE IN RELATION TO HAUL
DISTANCE. (FROM CATERPILLAR HANDBOOK, 1984).
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• The graph provides the uncorrected, maximum production. In order to adjust
to various conditions which affect production, correction factors are given in
Table 39. Adjustment factors for grade (pushing uphill or downhill) are given
in Figure 108
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• Table 39. Job condition correction
factors for estimating bulldozer earth
moving production rates. Values are for
track-type tractor equipped straight (S)
blade.
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TRACK TYPE TRACTOR
WHEEL TYPE TRACTOR
1.00
0.60
1.00
0.60
0.50
1.20
1.20
0.80
0.60
0.75
-
0.80
0.80
0.60 - 0.80
1.15 - 1.25
1.15 - 1.25
0.80
0.70
0.84
0.67
0.84
0.67
0.80
-
0.50 - 0.75
-
Cushioned (C) blade
0.50 - 0.75
0.50 - 0.75
D5 narrow gauge
0.90
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OPERATOR
Excellent
Average
Poor
MATERIAL
Loose stockpile
Hart to cut; frozen-with tilt cylinder
without tilt cylinder
cable controlled blade
Hard to drift; "dead" (dry, non-cohesive material)
or very sticky material
SLOT DOZING
SIDE BY SIDE DOZING
VISIBILITY -Dust, rain, snow, fog, darkness
JOB EFFICIENCY -50 min/hr
40 min/hr
DIRECT DRIVE TRANSMISSION
(0.1 min. fixed time)
BULLDOZER*
Angling (A) blade
0.75
0.70
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EXAMPLE
• Determine the average hourly production of a 200 hp
bulldozer (D7) equipped with a straight blade and tilt
cylinder. The soil is a hard packed clay, the grade is 15
percent favorable, and a slot dozing technique is used.
The average haul or push distance is 30 m. The soil
weight is estimated at 1,200 kg/m3 loose, with a load
factor of 0.769 (30 % swell). An inexperienced operated
is used. Job efficiency is 50 min/hour.
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EXAMPLE
The uncorrected maximum production is 430 m3 loose/hour (from
Figure 107) bulldozer curve D7S. Applicable correction factors are:
Job efficiency (50 min/hr)
0.84
Poor operator
0.60
Hard to cut soil
0.80
Slot dozing technique
1.20
Weight correction
0.87
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EXAMPLE
• Production = Maximum Production * Correction
Factor
• = (430 m3 loose/hr) (0.84) (0.60) (0.80) (1.20)
(0.87) = 181 m3 loose/hour
• Production (bank m3) = (181 m3 loose/hr)
(0.769) = 139 bank m3/hr
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END
Thank you for your attention
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