farm and machinery

1. Threshing
process of detaching grain from ear heads or plants
called threshing.
It separates grains from panicles, cobs and pods
Principle of threshing are impact of beater or spike
over grain and wearing or rubbing action.
crop material pushed into threshing cylinder through
feeding chute/trough/hopper/ conveyor.
Then gets into working clearance between
circumference of revolving drum fitted with spikes/ bars/
hammer around its periphery and upper concave casing
beneath it.
Grains falls on sieves, cleaning occur by blower or
aspirators and it handles by handling unit.

3. Threshing Methods
Threshing by manual labour: it slow & labour consuming,
process of beating crop on a floor or beating by stick.
Threshing by animal: crop spread on clean threshing space,
animal are tied in line one after other and move round & round
with help of strong pole. Thresh with hoop of animal
Threshing by Machines: machine operated by prime mover
such as electric motor, engine, tractor and power tiller.
Functions of power Thresher
1.feed the crop to threshing cylinder, thresh grain out of head
2.Separate the grain from straw & clean grain
3.put grain in a bag & make chaff suitable for animal feeding.

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4. Syndicator type: is a modification of chaff cutter, consists of
flywheel with corrugation on its periphery & sides. Cutter
blades have serrated edge to prevent slippage of dry stalk
5. Axial flow type: consists of spike tooth cylinder, wire woven
mesh concave & upper casing with helical louver
6. Wire loop type: number wire loop provided on periphery of
a cylinder & wire mesh provided at the bottom.
 Cleaning Unit: function of its is to separate & clean
threshed grain, consists of oscillating sieves, a fan & air
sucking duct known as Aspirator.
 Aspirator is a cleaning unit used for cleaning grain by
drawing air. Blower is a device to produce air blast.
 Winnowing fan used for creating air blast.

5. Components of Power Thresher
 Concave: is a metal grating, partly surrounding cylinder
against which cylinder rubs grain from plant
 Cylinder or Drum:
1. Spike/Peg tooth type: spike on cylinder so arrange that
pass in between the stationary teeth on concave
2. Hammer mill/ Drummy type: beaters attached with
beater arm at tip & rigidly fixed to hub which mounted
on main shaft.
3. Rasp bar type: number of corrugated steel bar
mounted on periphery of cylinder, threshing
accomplished between corrugated cylinder bar &
stationary bars on concave portion.

13. Pedal Thresher

14. Combine harvester
 It is a machine designed for harvesting, threshing,
cleaning and collecting the grain.
 Functions of combine harvester
1. Cutting the standing crops
2. Feeding the cut crops to threshing unit
3. Threshing the crops
4. Cleaning the grains from straw
5. Collecting the grains in a container
 Self propelled type
 Tractor operated

16. 1.Cutting knife 2. Feeding auger 3. stone trap 4. Threshing drum 5. concave casing 6.
Front conveying auger 7. Rear conveying auger 8. Blower 9. Preparation floor 10.
upper frog mouth sieve 11. Lower frog mouth sieve 12. clean grain auger 13. Return
auger 14. clean grain elevator
15. Grain tank filler auger

17. Cutting blade Knife Assembly

18. Threshing Unit

19. Cleaning Unit