Farm Machinery and Equipment-I 3(2+1)

Lesson 21. Earth moving equipment (Bulldozer, Trencher, Elevator etc.): construction and working principles

Principles & Types of Earthmoving Equipment

Earthmoving involves:    (i)Controlled cutting or loading

                                    (ii)moving, and

                                    (iii)Spreading or dumping of soil

Methods for moving the earth after cutting or loading:

a) Lifting and Rolling Action

Ex: M.B. Plow  used for terrace marking Disc Plow

b) Throwing Action

Ex: Auger plough (Whirlwind Terracer)

c) Pushing Action  ( is accompanied by some amount of rolling also)

Ex: Scrapers & graders of various kinds such as Bulldozers, Angle-dozers, V-drags, land smoothers (levelers).

d) Carrying Action:

• Scoops

• “Carry-all” scrapers

Machines commonly used for earthmoving jobs:

(1) Crane shovel

(2) Crawler Tractor

(3) Rubbles fixed tractor

(4) Towed Scraper

(5) Self-propelled scraper

(6) Dump trucks and wagons

(7) Motor graders

(8) Belt loader

(9) Elevating grader

(10) Air compressors

Angle-Blade Scrapers and Graders

• Used for moving soil to one side.  Also known as “Crowding”. By setting the blade at an acute angle from the direction of travel.

• Blade may also be set in the right-angled position for smoothening or moving moderate amounts of soil by direct pushing.

• Blades have provision for adjustment in all three planes.

• Size ranges from 2-3 m (for rear-mounted utility blades)

• Trailed, two-wheel blade graders (lower cost, better maneuverability and better penetration)

 Push-Type Scrapers

Buildozer is the most common tool that moves earth by pushing

Blades are also mounted on the front of a tractor

More heavy and rugged

When blades can be angled these are called as “angle-dozers”

Buldozer is a versatile tool adapted to a wide variety of jobs in the construction work

On the farm it is used for:

a)Land-clearing
b)Back-filling of ditches
c)Moving earth over relatively short-distances (Economical for handling earth to 50-60 meters only)

Trailed Scrapers of Push Type:

• Commonly known as “Land-levelers” have bottomless bowls with skirts added at the ends.

• Carried on wheels to control depth of cutting or spreading through a remote-cylinder.

• Width 2-5 m

• Bowl capacity : 1-4 cu m

• Power requirement: 50-60 hp

Brag-Type “Carry-all” Scrapers

(Roll-over scrapers)

• Load is supported by the bottom of the scraper bowl behind the cutting edge rather than pushing it.

• “Rotary or roll-over” scraper is a common example.

• Filling should take place in distance of 6-7 m at transport speed.

• Bowl is tipped backward for the blade to clear and loaded scraper is dragged on the bottom to the desired location.

• Emptying is done by releasing a latch.

• Roll over scrapers are inexpensive and efficient for small fields.

• Good for moderate hauling distances

• Capacity1/2 to 2 cu m.

Wheel-type Carrying Scrapers

• Self  loading

• Wheel type scrapers

• Capacity 1 to 30 cu m

• It can dig its own load, haul it on wheels and then spreading in controlled layers

• Loading is done by means of blade.

Land smoothing

• An essential operation for irrigated fields and also for drainage.

Blades-type long-span smoothers

• Effectiveness of land finishing is dependent on the span or bridging effect.

• “Long wheel-base” smoothers, are also known as “Land Planes”

A land plane consists of:

a) Long frame supported at each end by wheel or skids

b) An adjustable leveling blade at some intermediate point.

• Effective length or span:  10-27 m

• Width of cut : 2-5 m