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.

Thanking you

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