“TRACTOR AND RELATED EQUIPMENTS” A tractor is a versatile i.e. multipurpose machine. They convert engine energy into tractive energy. Classification of tractors: Wheeled Tractor Crawler Tractor

1. Prepared by
Prof. Ashish Makwana
Civil Engineering Dept. - MEFGI
Prof. Ashish Makwana 1

2. PRESENTATION
OUTLINE…
• Tractors
– Classification of tractors
– Factors affecting the selection of tractors
– Comparative study of wheeled and crawler tractor
– Rim pull
– Construction of tractor
– Gradability
– Advantages of wheel tractor
Prof. Ashish Makwana 2

3. PRESENTATION
OUTLINE…
• Bulldozers
– Purposes of Bulldozer
– Classification of bulldozers
– Size and output of a bulldozer
– Comparative advantage of crawler and wheel
mounted dozers
– Blades of a dozer
Prof. Ashish Makwana 3

4. PRESENTATION
OUTLINE…
• Rippers
– Rock ripping
– Determining the rippabillity of rock
– Physical characteristics that favour ripping
– Ripper attachments
– Output of rippers
Prof. Ashish Makwana 4

5. PRESENTATION
OUTLINE…
• Scrapers
– Scraper operation
– Classification of Scrapers
– Advantages and Disadvantages of scrapers
– Output of a scraper
– Factors affecting output of a scraper
Prof. Ashish Makwana 5

6. TRACTOR
• A tractor is a versatile i.e. multipurpose machine. They
convert engine energy into tractive energy.
Classification of tractors:
– Wheeled Tractor
– Crawler Tractor
Factors affecting the selection of tractors:
• The size required for the given job.
• The type of job for which the tractor is to be used as pulling
• The type of footing over which it will travel as wheeled i.e. low
or high tractive power unit
• The smoothness and firmness of the haul road.
• The slope of haul road and the length of haul.
• The type of work to be done after the completion of this job.
Prof. Ashish Makwana 6

7. TRACTOR (CONTINUED..)
Rim pull:
• The rim pull of tractor at any speed in the force between
the tyres of the driving wheels of the tractor and the
surface on which the tractor travels is called rim pull.
F. P. S. system, Rim pull =
375 x efficiency x h. p. of tractor
Speed in miles per hour
Lb
M. K. S. system, Rim pull =
275 x efficiency x metric h. p.
Speed in Km p. h.
kg
Prof. Ashish Makwana 7

8. TRACTOR (CONTINUED..)
Construction of tractor:
– Engine
– Engine Clutch
– Transmission system including power take off
– Ground drive and controls
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9. TRACTOR (CONTINUED..)
Gradability:
It is defined as the maximum slope expressed as a
percent, up to which a wheel type prime mover or a crawler
may move at a uniform speed.
k =
11660 x T x G
W x R
−
N
40
Where,
k = Gradability %
G = Total gear reduction for particular gear selected
T = Rated radius, the radius of the loaded driving wheels in cm.
N = Rolling resistance, kg/ton
W = Gross weight of complete unit, kg.
Prof. Ashish Makwana 9

10. BULLDOZER
• Dozers are machines designed primarily for cutting and
pushing material over relatively short distances.
Purposes of bulldozer:
• To clear the site of work
• To make the land level
• To prepare pilot roads through mountains and hard ground.
• To excavate the material and haul for a distance of about 100
meters.
• Spreading earth
• Backfilling trenches
• Maintaining haul roads
Prof. Ashish Makwana 10

11. BULLDOZER (CONTINUED..)
Classification of bulldozers:
• Cable controlled or hydraulic controlled
• Depending upon the mountings: crawler tractor mounted bulldozer
or wheel tractor mounted bulldozer
• Depending on the nature of blade: casting dozer or angle – dozer
Size and output of a bulldozer:
• Size of a bulldozer  dimensions of the blade
• Output  conditions under which it operates
Output of all the earth moving machinery  depend on following
factors:
• Efficiency of the operator
• Nature of soil
• Topography of the area
• Type of equipment
• Weather
Prof. Ashish Makwana 11

12. BULLDOZER (CONTINUED..)
Utility of a bulldozer:
• By suitable attachments to the bulldozer, it can be
utilized to remove trees, rocks, boulders, etc.
Blades of a dozer:
• The blades of a dozer are made from mold boards with
replaceable cutting edges and side bits. The blade is
connected to the dozer with the help of push arms and
tilt cylinders or a C frame.
Prof. Ashish Makwana 12

13. RIPPERS
• An equipment which is sometimes attached to a tractor.
• Mounted on the wheels and carries two to four teeth.
Rock Ripping:
• Rock can be ripped with the help of a ripper. Rock can
be ripped with the varying degree of success, for many
years but in recent years, the knowledge and
equipments for ripping the rocks have greatly increased.
Prof. Ashish Makwana 13

14. RIPPERS (CONTINUED..)
Major developments responsible for increased ripping
of rocks are as follows:
• Availability of heavier and more powerful dozers.
• Improvement in sizes and performance of rippers such
as development of impact rippers.
• Availability of better equipment for determining the
rippabillity of rocks.
• Availability of improved technique in using instruments
and equipment
Prof. Ashish Makwana 14

15. RIPPERS (CONTINUED..)
Determining the rippability of rocks:
• Rippabillity of rocks depends on the type of rock and its
density.
• To rip the igneous rocks is impossible as they have no
cleavage planes and stratification. Basalt, granite etc. come in
this category.
• Sedimentary rocks such as sand stone  layered structure &
characteristic of these rocs makes them easier to rip.
• Metaphoric rocks such as gneiss, quartzite slate etc. vary in
rippability with their degree of cleavage.
• Seismo graphic methods used for determining rippability
refraction
Prof. Ashish Makwana 15

16. RIPPERS (CONTINUED..)
Physical Characteristics that favour Ripping
• Faults, fractures, and joints
• Brittleness and crystalline structures
• Weathering
• High degree of lamination or stratification
• Large grain size
Prof. Ashish Makwana 16

17. RIPPERS (CONTINUED..)
Ripper attachments:
• The ripper attachments for dozers generally are rear
mounted. The mounting may be fixed radial, fixed
parallelogram with hydraulically variable pitch.
Prof. Ashish Makwana 17

18. RIPPERS (CONTINUED..)
Effectiveness of Ripper depends upon the following
factors:
• Properties of material to be ripped. As weathered,
faulted, laminated etc.
• Dozer’s usable power to advance the tip. It depends on
dozers weight and coefficient of friction.
• Down pressure at the ripper tip.
Prof. Ashish Makwana 18

19. RIPPERS (CONTINUED..)
Output of Rippers
Output of rippers depend upon the characteristics of soil, size
of the tractor dozer, speed of the machine, shape and size of the ripper
tooth, number of shanks used, and depth and width of ripping pass.
Production per hour
= Blank volume ripped per pass x (Number of passes per hour)
= Length of pass x Depth of penetration x Efficiency
Number of passes per hour =
60
Time for making one pass (in min)
Time taken in one pass =
Length of pass
Travelling speed
+ Turn round time
Prof. Ashish Makwana 19

20. SCRAPERS
 Scraper:
– consists of a large bucket
– attached to a tractor
– Capacity: 3 cum. to 9 cum.
– Cutting edge at the bottom
– Possible to dig earth to a depth of about 250 mm
– Combines three operations: Digging, Conveying and Dumping
Prof. Ashish Makwana 20

21. SCRAPERS (CONTINUED..)
Classification of scrapers:
• 1. Pusher – loaded (conventional)
– a. Single – powered axle
– b. Tandem – powered axles
• 2. Self-loading
– a. push-pull
Tandem-powered axles
– b. Elevating
– c. Auger
Prof. Ashish Makwana 21

22. SCRAPERS (CONTINUED..)
Output of a scraper:
• The number of trips per hour will depend on the time
required for operating and for a round trip.
• Time required to make a trip include:
– Loading
– Travelling to fill
– Dumping
– Turning
– Returning to the pit
– Getting back in position to load
Prof. Ashish Makwana 22

23. SCRAPERS (CONTINUED..)
Factors Affecting output of scrapers:
• Type of material to be handled
• Size of tractor
• Use of helper tractor during loading
• Condition of haul road
• Haul distance
• Slope of haul road
• Altitude
• Climate conditions
• Management conditions
• Size of borrow pit
• Condition of cut of borrow pit
• Degree of looseness of material before loading
• Slope of loading zone
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24. SCRAPERS (CONTINUED..)
Capacity of a Scraper: based on capacity of the bowl 1
cubic metre to 25 cubic metres
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