Here is a list of equipments used for threshing and harvesting of crops: 1. Paddy Thresher 2. Combine Harvester Thresher 3. Fruit Harvester.
Equipment # 1. Paddy Thresher:
Paddy thresher is the thresher used for threshing paddy. The threshing cylinder is of spike tooth type and the top cover has louvers to guide the crop axially. In the end of the cylinder there is a thrower for the paddy stalks. The thresher has also the cleaning mechanism and bagging attachments. It can be operated by a tractor, diesel engine or electric motor. The capacity may be 250-1000 kg/hr.
Paddy Thresher (Pedal Operated):
It consists mainly of a well-balanced cylinder with a series of threshing teeth fixed on wooden slats. It has got gear drive mechanism to transmit power. While the cylinder is kept in rotary motion at high speed, the paddy bundles of suitable sizes are applied to the teeth. The grains are separated by the combing as well as by hammering action of the threshing teeth.
This thresher mainly consists of:
1. Body Frame
2. Cylinder
3. Drive Mechanism
4. Axle
1. Body Frame:
The body frame of the paddy thresher consists of the base, the side frame, the front grain shield and rear grain shield.
(a) Base:
The base may be made of mild steel angle section or of wood. It is suitably fixed to the side frame of the body.
(b) Side Frame:
The side frame supports side boards which are usually made of mild steel sheet.
(c) Front Grain Shield:
The front grain shield is made of wooden plank of about 12 mm thickness and is fitted suitably to the side frames.
2. Cylinder:
The cylinder may be in two sizes. One size is about 450 mm in length when the thresher is operated by one man. The other size is 700 mm in length when it is to be operated by two persons. The cylinder has slats, cylinder end disc and threshing teeth.
(a) Slat:
Each wooden slat is fixed to the cylinder end discs by mortise and tendon joints.
(b) Cylinder End Disc:
The cylinder end disc may be webbed in order to reinforce them. There are mild steel bars, rolled or welded along the edges of the disc.
(c) Threshing Teeth:
Threshing teeth are fixed to the slats. They are curved in shape. The threshing teeth project out about the surface of the slats to a suitable height.
3. Drive Mechanism:
The drive of the pedal thresher is of eccentric type. Drive consists of a crank, one end of which is connected to a spur gear. The other end of the crank is connected suitably to the pedal frame fulcrum, which is welded to the pedal frame. The normal operating speed is about 400 revolutions per minute.
(a) Gear Housing:
Gear housing is made of cast iron. It consists of suitable spur gear which engages the pinion for transmitting power.
(b) Crank:
The crank is made of mild steel bar.
(c) Pedal Frame Fulcrum:
It is made of mild steel flat.
(d) Pedal Board:
The pedal board is made of wooden plank.
4. Axle:
The cylinder axle and the gear stub axle are made of mild steel round bar. The axle is supported by bearing with loose balls in cup and cones and is protected by suitable guards.
Equipment # 2. Combine Harvester Thresher:
It is a machine designed for harvesting threshing, separating, cleaning and collecting grains while moving through the standing crops. Bagging arrangement may be provided with a pick up attachment. It may be self-propelled or tractor operated.
The main functions of a combine are:
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
The whole machine is coupled of the following components:
1. Header
2. Reel
3. Cutter bar
4. Elevator canvas
5. Feeder canvas
6. Feeding drum
7. Threshing drum
8. Concave unit
9. Fan
10. Chauffer sieve
11. Grain sieve
12. Grain auger
13. Tailing auger
14. Tail board
15. Straw spreader
16. Return conveyor
17. Shaker
18. Grain elevator
19. Grain container
Header is used to cut and gather the grain and deliver it to the threshing cylinder. The straw is pushed back on the platform by the reel. Small combines use Scoop type headers, while large combines use T type headers with auger tables.
Harvesting is done by a cutting unit, which uses a cutter bar similar to that of a mower. The knife has got serrated edge to prevent the straw from slipping while in operation. There is a suitable cutting platform which is provided with a reel and a canvas.
The reel is made of wooden slats which help in feeding the crops to the cutting platform. The reel gets power through suitable gears and shafts. The reel revolves in front of the cutter bar, while working in the field. The reel pushes the standing crops towards the cutting unit. The reels are adjustable up and down as in or out.
The cutter bar of the combine operates like a cutter bar of a mower. It cuts the standing crops and pushes them towards the conveyor. The conveyor feeds the crop to the cylinder and concave unit. Canvas Table conveyors are mostly used with scoop type headers which have narrow cut.
Auger and canvas conveyers are used for narrow body machines which have wide cut. The grain is swept underneath the augers and conveyed behind them. The flights are often straightened out at the centre which works as paddles in feeding the grain to the under shot conveyor web. This delivers the grain to the cylinder.
In most of the machines, a beater in front of the cylinder, rotating in the same direction is used with under shot conveyors. This aids in stripping the crop from the conveyor and feeding it to the cylinder.
The threshing takes place between the cylinder and concave unit of the combine. The basic component of the threshing unit of the combine is similar to a power thresher. As soon as the crops are threshed, the threshed materials move to straw rake. These rakes keep on oscillating and separating the grains. The cleaning unit consists of a number of sieves and a fan.
The cleaning takes place on these sieves with the help of fan. The unthreshed grains pass through tailing auger and go for rethreshing. The clean grains pass through grain elevator and finally go to packing unit. Grains are collected in a hopper provided at the suitable place. The fan is adjusted such that the chaff etc. is blown off to the rear side of the machine. The size of the combine is indicated by the width of cut, it covers in the field.
A combine may be of following types:
1. Self-propelled type and
2. Pto driven type
Self-propelled combine has got its own independent engine. This engine gives power for operating all the mechanism as well as for pulling the weight of the combine. The size for the self-propelled machine varies from 2 to 4 metres.
The pto driven type combine is pulled by a tractor. The tractor pulls the combine by its tractive power. The power take- off shaft of the tractor supplies power to their cutting and threshing mechanism. The power requirement of the combine may be taken as 8 hp per metre width of cut for pulled type machine and 12 hp per metre width of cut for self-propelled type of machine.
Advantage of Combine Harvester Thresher:
1. It saves the cost of harvesting and threshing the crops.
2. It reduces the labour requirement of the field.
3. The grains can be obtained easily from the crops and thus the risks of fire, rain and other hazards are minimized.
4. It cleans the field earlier, which permits easy dry weather farming.
5. As the grains come in hand earlier, there is every possibility to get good profit in the market.
6. If the straw has to be used as organic manure, it can be done by spreading the straw at the time of harvesting itself.
Disadvantages:
1. Higher initial cost
2. Unadoptable for mixed farming
3. It cannot be used in fragmented piece of land
4. Heavy loss of grain and straw in the field
5. Operating and maintenance is costly.
Japanese Type Paddy Combine:
This type of combine is distinctly different from combines used in western countries. They are usually of self-propelled type using an engine of 8 to 10 hp. They are provided with oscillating cutter bar as in western combines.
The combines are provided with inclined gathering chains to carry the cut materials and feed the ear-heads into the thresher. The straw comes out from the side of the machine and it does not pass through the threshing, separating and cleaning units of the machine.
Japanese combines are 2 to 4 row machines. They are riding type as well as walking type both. To combat the problem of poor traction in paddy fields the Japanese combines are provided with special rubber crawler chains.
Equipment # 3. Fruit Harvester:
A Harvester, used for harvesting fruit is called “Fruit Harvester”.
The following are the traditional method of fruit harvesting:
1. Snatching or pulling of fruits by hand.
2. Hitting fruits, branches with a stick.
3. Shaking tree/branches.
These methods are quite crude and cause considerable damage to fruits and adversely affect their quality. Continuous efforts are made to improve the technology. As a result some manually operated methods are becoming popular. Machine operated fruit harvesters like western countries are not popular now in India.
The following are some improved types of manually operated fruit harvesters:
i. Bamboo Cone Type
ii. Wire Cone Type
iii. Push and Twist Type
iv. Pull and Cut Type
v. Hold and Twist Type
i. Bamboo Cone Type:
It is made of a long bamboo stick. One side of the stick is slit open with a sharp knife to a length of about 100 to 150 mm
The slit portion is given a shape of cone by inserting a piece of cloth or straw at their base and netting together with the help of a strong straw thread. A man holding the device in hand pushes up the cone to fruits. A little twist/jerk is given in case the fruit is not detached during the pushing action. When the cone is full, the fruits are unloaded in a basket at the ground.
ii. Wire-Cone Fruit Harvester:
It is a modified form of bamboo cone type. Steel wires and mild steel pipes are used instead of bamboo strips. It has projected mild steel spikes which help in easy detachment of fruits through better gripping.
iii. Push and Twist Type:
In this type, harvesting is done by pushing and twisting the fruit:
a. It consists of a ring 100 mm in diameter, made of 18 gauge carbon-steel-band saw blade.
b. The top edge is cut into six teeth of 40 cm height.
c. The ring is welded on a U-shaped frame over a 10 mm diameter M.S. rod that can be fitted to a handle.
d. A cloth conveyor is attached to the ring to avoid impact damage due to free fall of fruits after harvesting.
iv. Pull and Cut Type:
This device is based on the principle of scissors mechanism for cutting fruit stems:
a. The scissors blades can be mounted at different angles i.e. (i) Horizontal, (ii) Vertical, (iii) Inclined.
b. The blades are made of carbon steel.
c. They are actuated by pulling a cord over a pulley fitted on one of the blade handles.
d. A cloth conveyor over a steel ring just below the blades helps in collecting fruits after cutting.
e. The fruits requiring different removing forces could be easily harvested.
f. Fruits are saved from skin damage due to conveyor bag.
v. Hold and Twist Type:
This device is based on the hand picking mechanism where individual fruit is first held between two jaws of the harvester and then twisted to shear off the stalk.
The Jaws are made of 14 gauge M.S. sheet. They are held together by a tension spring on a pivot fitted on 10 mm MS bar. The bar can be fitted on a handle. One of the jaws has a lever bracket and rope arrangement for operating jaws movement.
3mm thick rubber sheet padding is provided on the inside of the jaws to avoid any skin damage, while holding fruits. After its detachment, fruit is released by pulling the cord into a ring and cloth conveyor arrangement provided below the jaws to take it to the ground without damage.