tractors & related equipment's (ace)
TRANSCRIPT
Prepared by, Sujith Velloor S
Lecturer
Civil Engg. Dept
Topic:-
Tractors & Related Equipment's
Subject:- ACE (2160602)
Gujarat Technological University
Tractors & Related Equipment's
Tractors are machines that converts engine energy into tractive
energy ( Pull or push)
Types
1. Crawler Type Tractors
2. Wheel Type Tractors
1. Two wheel type tractors
2. Four wheel type tractors
Factors affecting selection of equipment's
Size required for a given job.
Kind of job for which it will be used
Type of footing over which it will travel or its requires high or
low tractive efficiency
Firmness of haul road
Smoothness of haul road
Slope of haul road
Length of haul road
Crawler Tractors.
They are more compact and powerful and
can handle heavier job of hauling and
digging
They are costly due to their expensive track
system
They have slow speed of about 12kmph
Purposes
-A prime mover for pulling or pushing loads
-A power unit for winches and hoists
-A moving mount for bull dozer
Wheel Tractor
Wheel tractors equipped with pneumatic tyres, have been used
since 1938
They have speed about 50kmph.
There are two types.
Two wheel type
Four wheel type
Bull Dozer
A bulldozer is a tractor unit which has a blade attached to its
front. A blade is used to push, shear cut and roll the material
ahead of tractor.
Purpose
To Clean the site
Opening up temporary roads
Moving earth for haul distance up to 100m
Levelling earth works
Back filling trenches
Classification
According to direction of blades
Bulldozer- Machine mounted with blades perpendicular to direction of travel
Angledozer- Machine mounted with blades set at an angle with to direction of travel
According to mountings
Crawler mounted
Wheel mounted
According to method for raising & lowering blades
Cable Control
Hydraulic Control
Cable Control Hydraulic Control
It is simple in installation and
operation
It is easy to repair and
operation
There is less chance to
damage as blade can move up
and ride over rigid
obstruction
It is difficult in installation
and operation
It is difficult to repair and
operation
More precise settling of blade
can be maintained
It can produce high pressure
on the blade
Crawler Mounted Wheel Mounted
It can travel over muddy surface
It is able to operate in rocky formation
It can deliver greater tractive effort
even operating on soft footing or soft
loose mud
Travelling cost is Higher compared to
wheel mounted for considerable
distance
It has high travel speed
It can travel over paved highway
It can deliver less tractive effort even operating on soft footing or soft loose mud
Greater output is received when considerable travelling is necessary
Blade Adjustments
Tilting:- The vertical movement of blade end is known as tilt.
This movement is within the vertical plane of blade
Pitching:- The control which allow the operation to vary the
angle of attack to blade cutting edge with ground is pitch
It is movement of top of blade towards or away from tractor
Angling:- Turning the blade so that it is not perpendicular to
the direction of tractor travel is angling
Types of Blades
1. Straight S blade
2. Angle A blade
3. Universal U blade
4. Cushion C blade
Straight S blade
These are the blades used
primarily for excavation work.
They have no curvature in their
length.
The blade is normally heavy
duty and can be titled, Thus
facilitating penetration into
hard materials.
It may be equipped to pitch.
Angle A blade
An angle blade is wider
by 30 to 60cm than an S
blade.
It can be operated
straight or angled up to
maximum 25 degree left
or right
Universal U blade
It is wider than
straight blade and
outside edges are
canted forward about
25 degree. This
canting of edge
reduce the spillage of
loose material
making U blade
efficient for moving
big load overlong
distance.
4.Cushion C blade
The cushion blade are mounted
on large tractors which are used
primarily for push-loading
scrapers.
The rubber cushion and spring in
mounting allow dozer to absorb
the impact of contracting the
scraper push block.
The cushion blade has limited
utility in pushing material and
should not be used for
production bulldozing. It cannot
be titled, pitched and angled.
Rippers
Ripper attachments for tractors
are generally rear mounted.
The ripper are used to tear and
split hard ground, weak rocks
or old pavements and base
The heavy ripping can be done
with crawler tractors, because
of the power and tractive force
available from such machines.
Factors affecting increase in utilization
1. Heavier and more powerful
2. Improvement in size and
performance of rippers
3. Better instruments for
determining the rippability
(Rocks which propagate
sound waves at low
velocity) of rocks.
4. Improved techniques in
using instruments and
equipment's
Types
The mounted may be either radial , hinged or
parallelogram.
The vertical piece which may be forced down
into material to be ripped is known as shank.
At lower cutting end of shank a tooth (detachable)
is mounted.
There are straight(used for Blocky formation) and
curved shanks(used for laminated rocks or
pavements) available.
Scrappers
Tractor-pulled
scraper are used to
scrap load, haul and
dump materials
They are used in wide range of material type, including shot rocks and
are economical over a wide range of haul length and haul conditions.
Types
1. Push loaded scrapers
Single power axle
Tandem power axle
Push-pull, Tandem-power axle
Elevating scrapers
Types
1. Push loaded scrapers
The wheel type tractor scraper has high travel speed up to 45kmph on favorable haul roads.
1. Single power axle: Only 50 to 55% of total loaded weight comes on driving wheel.
2. Tandem powered units: initial cost 25% > single power axle, therefore they are considered as a specialized unit.
2. Push-pull scraper: these are Tandem powered units having a cushioned push block and bail on front and hook on rear above the usual push block.
3. Elevating scraper: It is equipped with horizontal flight which are operated by two and less elevator chain to which the ends of flight are connected.
.
Scraper Operations
1. Loading : A scraper is loaded by lowering the front end of bowl until the cutting edge enter the ground surface.
As the scraper moves forward a horizontal strip of material is forced in to bowl.
Hauling: The loaded scraper unit is hauled to a place where material is dumped.
Dumping: This consists of lowering the cutting edge, raising the apron and forcing the material out by means of movable ejector mounted at rear of bowl.
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