This document discusses various types of harvesting machines and their components. It describes harvesting operations as separating seeds from stalks when crops are ripe. Manual harvesting with sickles is time-consuming compared to machine harvesting. A vertical conveyor reaper cuts crops and conveys them vertically for binding. It has components like a cutter bar, star wheels, and conveyor belts. A reciprocating mower has a knife that reciprocates against stationary fingers to cut forage crops. Root crop harvesters perform operations like cutting tops, loosening crops from soil, cleaning, and depositing crops.

1. BAHIR DAR UNIVERSITY
BAHIR DAR INSTITUTE OF TECHNOLOGY (BiT)
FACULTY OF MECHANICAL AND INDUSTRIAL
ENGINEERING
Course Title: Agricultural Machinery
Technology(AEng5161)Technology(AEng5161)
Chapter-5
Harvesting Machine
By
Solomon Tekeste
(Lecturer)7/13/2018 1

2. Harvesting Operations
• Harvesting operations are one of the farm field
operation in which seeds are separated from the stalk on
which they grow. This is done when crops are ripened and
reached maturity.
• In order to achieve increased yield, the crops that are
cultivated should be harvested at appropriate harvestcultivated should be harvested at appropriate harvest
time and moisture content. Both delayed and early
harvesting results in decreased yield.
Definition
• The operation of cutting, picking, digging or any
combination of these for removing the whole crop or
edible part of the crop from either under the ground or
above the ground is called harvesting.

3. TERMS CONNECTED WITH HARVESTING
OPERATION
• Mower: It is a machine use to cut herbage crops and leave
them in a swath.
• Reaper: It is a machine to cut grain crops.
• Reaper binder: It is a machine which cuts the crops and
ties them into neat and uniform bundles.
• Sickle: It is a curved steel blade with sharp edge in the
inner side and a handle. It is used by human power. The
Sickle: It is a curved steel blade with sharp edge in the
inner side and a handle. It is used by human power. The
person holds the tool and shears the straw or stalk and
harvests the crop
• Swath: The harvested material laid on the land by the
machine when harvesting is in progress is called a swath.
• Windrow: It is a row of material formed by combining two
or more swaths.
• Windrower: It is a machine to cut crops and deliver them
in a uniform manner in a row.

4. Types of Harvesting
• There are different kinds of harvesting operations.
The main ones include:-
• Grain harvesting
• Root crop & Vegetable harvesting• Root crop & Vegetable harvesting
• Forage harvesting

5. Grain Harvesting
• Grain harvesting can be done by human labor or by
harvesting machines.
• Manual harvesting is time consuming and tedious.
• Timeliness of harvest is of very important. During
harvesting season, often rains and storms occurs causing
considerable damage to standing crops. Rapid harvest
facilitates extra days for land preparation and earlier
planting of the next crop. The use of machines can helpplanting of the next crop. The use of machines can help
to harvest at proper stage of crop maturity and reduce
drudgery and operation time.
• According to power source used harvesting tools can be
classifies as
• Manually operated tools
• Animal drawn implements
• Power driven machines

6. Manual Harvesting
• Manual harvesting is done
with sickles.
• Labors and time
consuming.
• It is used for harvesting
crops like wheat, teff,crops like wheat, teff,
paddy, sorghum etc.

7. VERTICAL CONVEYOR REAPER (VCR)
• It is used for harvesting of crops mostly at ground
level.
• It consists of crop row divider, star wheel, cutter
bar, and a pair of lugged canvass conveyor belts. This
type of machines cut the crops and conveys vertically
to one end and windrows the crops on the ground
uniformly.
to one end and windrows the crops on the ground
uniformly.
• Collection of crop for making bundles is easy and it is
done manually. Self-propelled walking types, self-
propelled riding type and tractor mounted type
reaper-windrowers are available.
• In this section the main design parameters of reapers
will be discussed.

8. Parts of vertical conveyor reaper & their design
parameters

9. R

10. Parts of vertical
conveyor reaper
1. Handle
2. Engine
3. Lugged Wheel
4. Belt Conveyor
5. Crop Row Dividers5. Crop Row Dividers
6. Star Wheels

11. Design of Crop Cutting Unit of VCR
• Crop Cutting Unit of VCR
1. Cutter bar
2. Knife section
3. Triangular/Curved plate
4. Pinion Shaft
5. Crank Pin

12. 1. Forces Acting on Cutter Bar of a Reaper
– Forces acting on cutter bar ( P): The total resisting force
(P) acting on the cutter bar is the sum of all the forces
acting on the knife
2. Selection of Cutting Unit of VCR
– Length of cutter bar
– Type of cutter bar:
Design of Crop Cutting Unit of VCR
– Type of cutter bar:
– Selection of guards
– Size and shape of knife sections
• Gripping of stalk by cutting pair
• Rake angle, sharpness and thickness of cutting edge
• Pitch of serrated knives
• Clearance between knife section and twin guard
• Velocity of knife sections
• Forward speed of the machine

13. Design of Crop Lifter and Divider
• The crop divider guides the
machine to insert the lifters in the
crop smoothly for proper cutting
or harvesting of the crop.
• When the machine travels at the
designed speed in the field, the
crop lifter guides the crop to thecrop lifter guides the crop to the
cutter bar with the help of star
wheel and the crop is cut by the
cutter.
• In designing crop lifters and
dividers the following factors has
to be determined.
– Minimum star wheel velocity
– Cover angle of lifters:

14. Crop Supporting Unit of VCR
•

15. Lugged Belt Conveyor/draper
• The cut crop is conveyed to one side by the lugged
belt conveyor at an angle of 90° for easy collection
and bundling. For this purpose the conveyor of the
machine must convey the bunch of cut crop on a
vertical platform continuously and without blockage.
Design ConsiderationsDesign Considerations
• Speed of lugged belt
• Pitch of lugs
• Number of lugs on belt
• Length of lugged belt of
conveyor:
• Lug height and clearance

16. MOWER
• Mower is a machine to cut herbage crops and leave
them in a swath. Animal drawn and tractor operated
mowers are available. According to the cutting tool
mowers are classified in to the following types such
as:as:
– Cylinder mower
– Reciprocating mower
– Horizontal rotary mower
– Gang mower and
– Flail mower

17. MOWER
1. Cylinder mower: It has rotating helical blades
arranged in cylindrical form. With the rotation of
blades, forage or grasses are cut continuously. It is
used for trimming grass in lawns, golf grounds etc.
2. Reciprocating mower: It is a mower with a knife2. Reciprocating mower: It is a mower with a knife
made of several serrated triangular sections that
reciprocate against stationary fingers. The knife
cuts the crop by its reciprocating action. It is the
most common type of mower used for harvesting
forage crops and food grain crops like paddy and
wheat.

18. Reciprocating mower

19. Parts of a Cutter Bar

20. MOWER
3. Horizontal rotary mower: It is a mower with high
speed knife rotating in the horizontal plane. Due to
rotation of knife, the grass and forage are cut
uniformly. Used for trimming lawns, golf grounds etc.
4. Gang mower: It is an assembly of two or more4. Gang mower: It is an assembly of two or more
ground driven cylinder mowers. It is used for
trimming grass in lawns, golf grounds etc.
5. Flail mower: It is a mower with high speed swinging
knives, operating either in the horizontal plane or in
the vertical plane.. Used to cut herbaceous weeds
like parthenium

21. Horizontal rotary mower

22. Root Crop Harvesting
• Root crops that need mechanical harvesters are potato,
sugar beet, ground nut, carrot and onion. The basic
operations performed in mechanical harvesting of root
crops are:
– cutting of the unwanted top portion at a desired height
– appropriate disposition of the tops to prevent interference
with the other steps
– digging or loosening the crops from the soil just below the
tuber zone
– elevating the crops and separating them from clods and
other foreign materials
– depositing the cleaned in a truck or trailer or in a tank on
the harvester

23. Reference
1. Ajit K. Srivastava et. al. 2012. Engineering Principles
of Agricultural Machines. Second Edition. American
Society of Agricultural and Biological Engineers.
2. D. N. Sharma and S. Mukesh. 2010. Farm Machinery
Design Principles and Problems. Second Edition.
Pusa Agri-Book Service, IARI, New Delhi.Pusa Agri-Book Service, IARI, New Delhi.
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